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As filed with the Securities and Exchange Commission on March 6, 2013

Registration No. 333-           

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

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Form S-3

REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933

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BankUnited, Inc.
(Exact Name of Registrant as Specified in Its Charter)

14817 Oak Lane
Miami Lakes, Florida 33016
(305) 569-2000
(Address, Including Zip Code, and Telephone Number, Including Area Code, of Registrant's Principal Executive Offices)

John A. Kanas
Chairman, President and Chief Executive Officer
BankUnited, Inc.
14817 Oak Lane
Miami Lakes, Florida 33016
(305) 569-2000
(Name, address, including zip code, and telephone number, including area code, of agent for service)

With a copy to:

Richard B. Aftanas, Esq.
Skadden, Arps, Slate, Meagher & Flom LLP
Four Times Square
New York, NY 10036
Telephone: (212) 735-3000

          Approximate date of commencement of proposed sale to the public: From time to time after the effective date of this registration statement as determined by the Registrant.

          If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box. o

          If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box. ý

          If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

          If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. o

          If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box. ý

          If this Form is a post-effective amendment to a registration to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box. o

          Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act. (Check one):

CALCULATION OF REGISTRATION FEE

(1)

Not applicable pursuant to Form S-3 General Instruction II.E.

(2)

We are registering an indeterminate number of shares of common stock, which may be offered from time to time in unspecified numbers and at indeterminate prices, and as may be issued upon conversion, redemption, repurchase or exchange thereof.

(3)

In accordance with Rules 456(b) and 457(r) under the Securities Act, the registrant is deferring payment of the entire registration fee.

   

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PROSPECTUS

COMMON STOCK

        This prospectus relates solely to sales of our common stock by selling stockholders. The selling stockholders, who will be named in a prospectus supplement, may offer and sell shares of our common stock from time to time in amounts, at prices and on terms that will be determined at the time of any such offering. We will not receive any proceeds from the sale of shares of common stock to be offered by the selling stockholders.

        This prospectus describes some of the general terms that may apply to our common stock. Each time any common stock is offered pursuant to this prospectus, we will provide a prospectus supplement and attach it to this prospectus. The prospectus supplement will contain more specific information about the offering, including the number of shares of our common stock to be sold by the selling stockholders. The prospectus supplement may also add, update or change information contained in this prospectus. You should read this prospectus and the accompanying prospectus supplement carefully before you make your investment decision.

        This prospectus may not be used to offer and sell shares of our common stock unless accompanied by a prospectus supplement or a free writing prospectus.

        The shares of our common stock may be sold at fixed prices, prevailing market prices at the times of sale, prices related to the prevailing market prices, varying prices determined at the times of sale or negotiated prices. The shares of our common stock offered by this prospectus and the accompanying prospectus supplement may be offered by the selling stockholders directly to investors or to or through underwriters, dealers or other agents. The prospectus supplement for each offering will describe in detail the plan of distribution for that offering and will set forth the names of any underwriters, dealers or agents involved in the offering and any applicable fees, commissions or discount arrangements.

        Our common stock is listed for trading on the New York Stock Exchange under the symbol "BKU."

        Investing in our securities involves a high degree of risk. See "Risk Factors" on page 1 before you make your investment decision.

        Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus or the accompanying prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is March 6, 2013.

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ABOUT THIS PROSPECTUS

        This prospectus is part of an automatic shelf registration statement that we filed with the Securities and Exchange Commission, or SEC, as a "well-known seasoned issuer" as defined in Rule 405 under the Securities Act of 1933, as amended, which we refer to as the Securities Act. Under the automatic shelf process, the selling stockholders to be named in a prospectus supplement may offer and sell, from time to time, shares of our common stock. We will also be required to provide a prospectus supplement containing specific information about the selling stockholders and the terms on which our common stock is being offered and sold. We may also add, update or change in a prospectus supplement information contained in this prospectus.

        You should rely only on the information contained in this prospectus and the accompanying prospectus supplement, including the information incorporated by reference herein as described under "Where You Can Find More Information," and any free writing prospectus that we prepare and distribute. Neither we nor the selling stockholders have authorized anyone to provide you with information different from that contained in or incorporated by reference into this prospectus, the accompanying prospectus supplement or any such free writing prospectus.

        The selling stockholders may only offer to sell, and seek offers to buy, shares of our common stock in jurisdictions where offers and sales are permitted.

        This prospectus and any accompanying prospectus supplement or other offering materials do not contain all of the information included in the registration statement as permitted by the rules and regulations of the SEC. For further information, we refer you to the registration statement on Form S-3, including its exhibits. We are subject to the informational requirements of the Securities Exchange Act of 1934, as amended, or the Exchange Act, and, therefore, file reports and other information with the SEC. Statements contained in this prospectus and any accompanying prospectus supplement or other offering materials about the provisions or contents of any agreement or other document are only summaries. If SEC rules require that any agreement or document be filed as an exhibit to the registration statement, you should refer to that agreement or document for its complete contents.

        You should not assume that the information in this prospectus, any prospectus supplement or any other offering materials is accurate as of any date other than the date on the front of each document. Our business, financial condition, results of operations and prospects may have changed since then.

        Unless we state otherwise or the context otherwise requires, references in this prospectus to "we," "our," "us," and the "Company" refer to BankUnited, Inc., a Delaware corporation, and its consolidated subsidiaries.

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WHERE YOU CAN FIND MORE INFORMATION

        We file annual, quarterly and special reports, prospectus and other information with the SEC. You may read and copy any document we file at the SEC's Public Reference Room at 100 F Street, N.E., Washington, D.C. 20549. You may obtain information on the operation of the Public Reference Room by calling the SEC at 1-800-SEC-0330. The SEC maintains an Internet site that contains our reports, proxy and other information regarding us at http://www.sec.gov. Our SEC filings are also available free of charge at our website (www.bankunited.com). The information on our website is not incorporated by reference into this prospectus.

        The SEC allows "incorporation by reference" into this prospectus of information that we file with the SEC. This permits us to disclose important information to you by referencing these filed documents. Any information referenced this way is considered to be a part of this prospectus and any information filed by us with the SEC subsequent to the date of this prospectus automatically will be deemed to update and supersede this information. We incorporate by reference the following documents which we have filed with the SEC (excluding any portions of such documents that have been "furnished" but not "filed" for purposes of the Exchange Act):

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our Annual Report on Form 10-K for the year ended December 31, 2012, which we filed with the SEC on February 25, 2013;



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the information specifically incorporated by reference into our Annual Report on Form 10-K for the year ended December 31, 2011 from our Definitive Proxy Statement on Schedule 14A, which we filed with the SEC on April 4, 2012; and



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the description of our common stock set forth in our registration statement on Form 8-A filed on January 18, 2011.

        We incorporate by reference any filings made with the SEC in accordance with Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act on or after the date of this prospectus and the date all of the securities offered hereby are sold or the offering is otherwise terminated, with the exception of any information furnished under Item 2.02 and Item 7.01 of Form 8-K, which is not deemed filed and which is not incorporated by reference herein. Any such filings shall be deemed to be incorporated by reference and to be a part of this prospectus from the respective dates of filing of those documents.

        We will provide to each person, including any beneficial owner, to whom a prospectus is delivered, without charge, upon written or oral request, a copy of any or all of the documents that are incorporated by reference into this prospectus but not delivered with this prospectus, excluding any exhibits to those documents unless the exhibit is specifically incorporated by reference as an exhibit in this prospectus. You should direct requests for documents to:

BankUnited, Inc.
Investor Relations
14817 Oak Lane
Miami Lakes, Florida 33016
(305) 569-2000

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FORWARD-LOOKING STATEMENTS

        This prospectus contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that reflect the Company's current views with respect to, among other things, future events and financial performance. Words such as "anticipates," "expects," "intends," "plans," "believes," "seeks," "estimates" and similar expressions identify forward-looking statements. These forward-looking statements are based on the historical performance of the Company or on the Company's current plans, estimates and expectations. The inclusion of this forward-looking information should not be regarded as a representation by the Company that the future plans, estimates or expectations so contemplated will be achieved. Such forward-looking statements are subject to various risks and uncertainties and assumptions relating to the Company's operations, financial results, financial condition, business prospects, growth strategy and liquidity. If one or more of these or other risks or uncertainties materialize, or if the Company's underlying assumptions prove to be incorrect, the Company's actual results may vary materially from those indicated in these statements. A number of important factors could cause actual results to differ materially from those indicated by the forward-looking statements, including, but not limited to, the risk factors described in Part I, Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2012. The Company does not undertake any obligation to publicly update or review any forward-looking statement, whether as a result of new information, future developments or otherwise.

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THE COMPANY

        BankUnited, Inc. is a national bank holding company with three direct wholly-owned subsidiaries: BankUnited, National Association ("BankUnited"), Herald National Bank ("Herald"), and BankUnited Investment Services, Inc. ("BUIS"). BankUnited, a national banking association headquartered in Miami Lakes, Florida with $11.7 billion of assets as of December 31, 2012, provides a full range of banking services to individual and corporate customers through 98 branches located in 15 Florida counties. Herald is a national banking association with 2 branch locations in New York. BUIS is a Florida insurance agency providing wealth management and financial planning services. The operations of BUIS have not historically been significant to the results of operations or financial position of the Company. We intend to discontinue the operations of BUIS in 2013.

        The Company has built, through organic growth and acquisitions, a premier regional bank with a low-risk, long-term value-oriented business model focused on small and medium sized businesses and consumers. We endeavor to provide personalized customer service and offer a full range of traditional banking products and services to both our commercial and retail customers.

Corporate Information

        Our principal executive offices are located at 14817 Oak Lane, Miami Lakes, Florida 33016. Our telephone number is (305) 569-2000. Our Internet address is www.bankunited.com. Information on, or accessible through, our website is not part of this prospectus.

RISK FACTORS

        You should consider the specific risks described in our Annual Report on Form 10-K for the year ended December 31, 2012, the risk factors described under the caption "Risk Factors" in any applicable prospectus supplement and any risk factors set forth in our other filings with the SEC, pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, before making an investment decision. Based on the information currently known to us, we believe that the information incorporated by reference in this prospectus identifies the most significant risk factors affecting our company. Each of risks described in these documents could materially and adversely affect our business, financial condition, results of operations and prospects, and could result in a partial or complete loss of your investment. The risks and uncertainties are not limited to those set forth in the risk factors described in these documents. Additional risks and uncertainties not presently known to us or that we currently believe to be less significant than the risk factors incorporated by reference herein may also adversely affect our business. In addition, past financial performance may not be a reliable indicator of future performance and historical trends should not be used to anticipate results or trends in future periods.

USE OF PROCEEDS

        All shares of common stock sold pursuant to this prospectus will be sold by the selling stockholders and we will not receive any of the proceeds from such sales.

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DESCRIPTION OF CAPITAL STOCK

        The following descriptions include summaries of the material terms of our amended and restated certificate of incorporation, our amended and restated by-laws and the applicable provisions of the Delaware General Corporation Law, or the DGCL. For more information on how you can obtain our amended and restated certificate of incorporation and our amended and restated by-laws, see "Where You Can Find More Information." We urge you to read our amended and restated certificate of incorporation and our amended and restated by-laws in their entirety.

General

        Our amended and restated certificate of incorporation authorizes us to issue up to 400,000,000 shares of common stock, $0.01 par value per share, and 100,000,000 shares of preferred stock, $0.01 par value per share.

        At February 20, 2013, there were outstanding:

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95,038,213 shares of our common stock held by approximately 577 stockholders; and



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5,415,794 shares of our Series A preferred stock held by one stockholder.

Common Stock

Voting Rights

        Each holder of our common stock is entitled to one vote for each share on all matters submitted to a vote of the holders of our common stock, voting together as a single class, including the election of directors. Our stockholders do not have cumulative voting rights in the election of directors. Accordingly, holders of a majority of the voting shares are able to elect all of the directors.

Dividends

        Subject to the prior rights of holders of preferred stock, holders of our common stock are entitled to receive dividends, if any, as may be declared from time to time by our board of directors.

Liquidation

        Subject to the prior rights of our creditors and the satisfaction of any liquidation preference granted to the holders of any then outstanding shares of preferred stock, in the event of our liquidation, dissolution or winding up, holders of our common stock will be entitled to share ratably in the net assets legally available for distribution to stockholders.

Preferred Stock

General

        Our board of directors has the authority, without action by our stockholders, to issue preferred stock and to fix voting powers for each class or series of preferred stock, and to provide that any class or series may be subject to redemption, entitled to receive dividends, entitled to rights upon dissolution, or convertible or exchangeable for shares of any other class or classes of capital stock. The rights with respect to a series or class of preferred stock may be greater than the rights attached to our common stock. It is not possible to state the actual effect of the issuance of any shares of our preferred stock on the rights of holders of our common stock until our board of directors determines the specific rights attached to that preferred stock. The effect of issuing preferred stock could include, among other things, one or more of the following:

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restricting dividends with respect to our common stock;

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diluting the voting power of our common stock or providing that holders of preferred stock have the right to vote on matters as a class;



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impairing the liquidation rights of our common stock; or



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delaying or preventing a change of control of us.

Series A Nonvoting Convertible Preferred Stock

        In February, 2012, the Company created a series of 5,415,794 shares of preferred stock designated "Series A Nonvoting Convertible Preferred Stock", par value $0.01 per share. The preferred stock ranks pari passu with the Company's common stock with respect to the payment of dividends or distributions and has a liquidation preference of $0.01 per share. Subject to certain restrictions, each share of preferred stock is convertible into one share of common stock at the option of the holder or upon written request of the Company and is mandatorily convertible into common stock upon certain transfers. For additional information, see "Certain Related Party Relationships—Blackstone Exchange Agreement" in our Definitive Proxy Statement on Schedule 14A, which we filed with the SEC on April 4, 2012.

Registration Rights

        BankUnited, Inc., certain funds affiliated with Blackstone Private Equity Group, or "Blackstone," the Carlyle Group, or "Carlyle," Centerbridge Partners, L.P., or "Centerbridge," and WL Ross & Co. LLC, or "WL Ross," all together referred to as the "Sponsors," and each individually as a "Sponsor," John A. Kanas, John Bohlsen, Rajinder P. Singh, and Douglas J. Pauls (together with Messrs. Kanas, Bohlsen and Singh, the "Management Members"), LF Moby LLC (which is beneficially owned by Richard S. LeFrak and his sons), Eugene F. DeMark, Ambassador Sue M. Cobb, and all other members of BU Financial Holdings LLC, previously the sole stockholder of BankUnited, Inc., entered into a registration rights agreement on February 2, 2011.

        Pursuant to the registration rights agreement, the Sponsors have been provided with demand registration rights, which became exercisable after expiration of the lockup provisions applicable to them. The demand registration rights require BankUnited, Inc. to register the shares of common stock beneficially owned by the demanding Sponsor with the SEC for sale by it to the public in a non-shelf registered offering, provided that the value of the registrable securities proposed to be sold by such demanding Sponsor is at least the lesser of $50.0 million or the value of all registrable securities held by such Sponsor. Subject to certain restrictions, any demanded non-shelf registered offering may, at BankUnited, Inc.'s option, include shares to be sold by BankUnited, Inc. for its own account and will also include shares to be sold by stockholders that exercise their related piggyback rights in accordance with the registration rights agreement. The registration rights provisions also provide that BankUnited, Inc. may be required under certain circumstances to file a shelf registration statement for an offering to be made on a continuous basis pursuant to Rule 415 of the Securities Act. BankUnited, Inc. may postpone the filing of such a registration statement or suspend the effectiveness of any registration statement for a reasonable "blackout period" not in excess of 90 days if BankUnited, Inc.'s board of directors determines that such registration or offering could materially interfere with a bona fide business or financing transaction of BankUnited, Inc. or is reasonably likely to require premature disclosure of material, non-public information, the premature disclosure of which BankUnited, Inc.'s board of directors reasonably determines in the exercise of its good faith judgment would not be in the best interests of BankUnited, Inc.; provided that BankUnited, Inc. shall not postpone the filing of a registration statement or suspend the effectiveness of any registration statement for more than 90 days in the aggregate in any 360-day period.

        In addition, pursuant to the registration rights agreement, in the event that BankUnited, Inc. is registering additional shares of common stock for sale to the public, whether on its own behalf (except

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with respect to registered primary offerings by BankUnited, Inc. (i) covered by a Form S-4 registration statement, Form S-8 registration statement or a successor form applicable to employee benefit-related or stock compensation and incentive offers and sales or (ii) where the shares are not being sold for cash) or through a demand registration on behalf of a Sponsor (as described above), BankUnited, Inc. is required to give notice of such registration to all parties to the registration rights agreement that hold registrable securities (which includes members of BankUnited, Inc. management that hold shares of BankUnited, Inc. common stock) of the intention to effect such a registration. Such notified persons have piggyback registration rights providing them the right to have BankUnited, Inc. include the shares of common stock owned by them in any such registration if BankUnited, Inc. has received written requests for inclusion therein within prescribed time limits, subject to other provisions under the registration rights agreement.

Corporate Opportunity

        Our amended and restated certificate of incorporation provides that the doctrine of "corporate opportunity" will not apply against the Sponsors, any of their affiliates or any of our directors or officers, and that the Company renounces any interest or expectancy in any business opportunities that are presented to any of the Sponsors or any of their affiliates or to any of the directors or officers of the Company, even if such opportunity is of a character that could be taken by the Company. To the extent that the Sponsors, any of their affiliates, or any of our directors and officers participate in any such business opportunity, they may have differing interests than our other stockholders.

Anti-Takeover Considerations and Special Provisions of our Certificate of Incorporation, By-Laws and Delaware Law

        The following sets forth certain provisions of the DGCL, and our amended and restated certificate of incorporation and our amended and restated by-laws. Banking laws also impose notice approval and ongoing regulatory requirements on any stockholder or other party that seeks to acquire direct or indirect "control" of an FDIC-insured depository institution. For additional information, see "Business—Regulation and Supervision—Notice and Approval Requirements Related to Control" in Part I, Item 1 of our Annual Report on Form 10-K for the year ended December 31, 2012.

Requirements for Advance Notification of Stockholder Nominations and Proposals

        Our amended and restated certificate of incorporation and amended and restated by-laws establish advance notice procedures with respect to stockholder proposals and the nomination of candidates for election as directors, other than nominations made by or at the direction of our board of directors or a committee of our board of directors.

Stockholder Meetings

        Our amended and restated certificate of incorporation and amended and restated by-laws provide that special meetings of the stockholders may be called for any purpose or purposes at any time by a majority of our board of directors or by the Chief Executive Officer or the President. In addition, our amended and restated certificate of incorporation provide that a holder, or a group of holders, of capital stock holding 25.0% or more of the total voting power of the outstanding shares of our capital stock may cause us to call a special meeting of the stockholders for any purpose or purposes at any time.

No Action by Stockholders Without a Meeting

        Our amended and restated certificate of incorporation and amended and restated by-laws provide that stockholders are not entitled to act by written consent.

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Amendments to our Amended and Restated By-Laws

        Our board of directors, by the affirmative vote of at least a majority of the board of directors, has the power without the assent or vote of the stockholders to adopt, amend, alter or repeal the by-laws. The by-laws also may be adopted, amended, altered or repealed by the affirmative vote of the holders of a majority of the votes entitled to be cast by the shares of outstanding capital stock entitled to vote thereon, subject to a specified exception relating to indemnification and advancement of expenses.

No Cumulative Voting

        The DGCL provides that stockholders are not entitled to the right to cumulate votes in the election of directors unless an entity's certificate of incorporation provides otherwise. Our amended and restated certificate of incorporation and amended and restated by-laws do not provide for cumulative voting in the election of directors.

Director Removal

        Except as may otherwise be required by applicable law and subject to the rights of holders of preferred stock then outstanding, our amended and restated certificate of incorporation and amended and restated by-laws will provide that stockholders may not remove directors without cause.

"Blank Check" Preferred Stock

        Our amended and restated certificate of incorporation and amended and restated by-laws authorize the issuance of "blank check" preferred stock with such designations, rights and preferences as may be determined from time to time by our board of directors.

Section 203

        We have elected to "opt out" of Section 203 of the DGCL, which prohibits a Delaware corporation from engaging in any business combination with any interested stockholder for a period of three years after the date that such stockholder became an interested stockholder, with the following exceptions:

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before such date, our board of directors approved either the business combination or the transaction that resulted in the stockholder becoming an interested holder;



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upon completion of the transaction that resulted in the stockholder becoming an interested stockholder, the interested stockholder owned at least 85.0% of the voting stock of the corporation outstanding at the time the transaction began, excluding for purposes of determining the voting stock outstanding (but not the outstanding voting stock owned by the interested stockholder) those shares owned (i) by persons who are directors and also officers and (ii) employee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or



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on or after such date, the business combination is approved by the board of directors and authorized at an annual or special meeting of the stockholders, and not by written consent, by the affirmative vote of the holders of at least 66²/3% of the outstanding voting stock that is not owned by the interested stockholder.

In general, Section 203 defines business combination to include the following:

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any merger or consolidation involving the corporation and the interested stockholder;

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any sale, transfer, pledge, or other disposition of 10.0% or more of the assets of the corporation involving the interested stockholder;



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subject to certain exceptions, any transaction that results in the issuance or transfer by the corporation of any stock of the corporation to the interested stockholder;



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any transaction involving the corporation that has the effect of increasing the proportionate share of the stock or any class or series of the corporation beneficially owned by the interested stockholder; or



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the receipt by the interested stockholder of the benefit of any loans, advances, guarantees, pledges, or other financial benefits by or through the corporation.

        In general, Section 203 defines an "interested stockholder" as an entity or person who, together with the person's affiliates and associates, beneficially owns, or within three years prior to the time of determination of interested stockholder status did own, 15.0% or more of the outstanding voting stock of the corporation.

        A Delaware corporation may "opt out" of Section 203 with an expressed provision in its original certificate of incorporation or an expressed provision in its certificate of incorporation or by-laws resulting from amendments approved by holders of at least a majority of the corporation's outstanding voting shares.

Listing

        Our common stock is listed on the New York Stock Exchange under the symbol "BKU."

Transfer Agent and Registrar

        The transfer agent and registrar for our common stock is the Registrar and Transfer Company.

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SELLING STOCKHOLDERS

        Information regarding the beneficial ownership of our common stock by the selling stockholders, the number of shares being offered by the selling stockholders and the number of shares beneficially owned by the selling stockholders after the applicable offering, where applicable, will be set forth in a prospectus supplement, in a post-effective amendment, or in filings we make with the SEC under the Exchange Act which are incorporated by reference.

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PLAN OF DISTRIBUTION

        The selling stockholders may sell the securities offered by this prospectus from time to time in one or more transactions, including without limitation:

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directly to one or more purchasers;



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through agents;



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to or through underwriters, brokers or dealers; or



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through a combination of any of these methods.

        In addition, the manner in which the selling stockholders may sell some or all of the securities covered by this prospectus includes any method permitted by law, including, without limitation, through:

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a block trade in which a broker-dealer will attempt to sell as agent, but may position or resell a portion of the block, as principal, in order to facilitate the transaction;



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purchases by a broker-dealer, as principal, and resale by the broker-dealer for its account;



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ordinary brokerage transactions and transactions in which a broker solicits purchasers; or



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privately negotiated transactions.

        The selling stockholders may also enter into hedging transactions. For example, the selling stockholders may:

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enter into transactions with a broker-dealer or affiliate thereof in connection with which such broker-dealer or affiliate will engage in short sales of the common stock pursuant to this prospectus, in which case such broker-dealer or affiliate may use shares of common stock received from the selling stockholders to close out its short positions;



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sell securities short and redeliver such shares to close out the short positions;



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enter into option or other types of transactions that require the selling stockholders to deliver common stock to a broker-dealer or an affiliate thereof, who will then resell or transfer the common stock under this prospectus; or



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loan or pledge the common stock to a broker-dealer or an affiliate thereof, who may sell the loaned shares or, in an event of default in the case of a pledge, sell the pledged shares pursuant to this prospectus.

        The securities covered by this prospectus may be sold:

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on a national securities exchange;



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in the over-the-counter market; or



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in transactions otherwise than on an exchange or in the over-the-counter market, or in combination.

        In addition, the selling stockholders may enter into derivative or hedging transactions with third parties, or sell securities not covered by this prospectus to third parties in privately negotiated transactions. In connection with such a transaction, the third parties may sell securities covered by and pursuant to this prospectus and an applicable prospectus supplement or pricing supplement, as the case may be. If so, the third party may use securities borrowed from the selling stockholders or others to settle such sales and may use securities received from the selling stockholders to close out any related short positions. The selling stockholders may also loan or pledge securities covered by this prospectus and an applicable prospectus supplement to third parties, who may sell the loaned securities or, in an

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event of default in the case of a pledge, sell the pledged securities pursuant to this prospectus and the applicable prospectus supplement or pricing supplement, as the case may be.

        A prospectus supplement with respect to each offering of securities will state the terms of the offering of the securities, including:

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the name or names of any underwriters or agents and the amounts of securities underwritten or purchased by each of them, if any;



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the public offering price or purchase price of the securities and the net proceeds to be received by the selling stockholders from the sale;



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any delayed delivery arrangements;



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any underwriting discounts or agency fees and other items constituting underwriters' or agents' compensation;



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any discounts or concessions allowed or reallowed or paid to dealers; and



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any securities exchange or markets on which the securities may be listed.

        The offer and sale of the securities described in this prospectus by the selling stockholders, the underwriters or the third parties described above may be effected from time to time in one or more transactions, including privately negotiated transactions, either:

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at a fixed price or prices, which may be changed;



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at market prices prevailing at the time of sale;



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at prices related to the prevailing market prices; or



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at negotiated prices.

General

        Any public offering price and any discounts, commissions, concessions or other items constituting compensation allowed or reallowed or paid to underwriters, dealers, agents or remarketing firms may be changed from time to time. Any selling stockholders, underwriters, dealers, agents and remarketing firms that participate in the distribution of the offered securities may be "underwriters" as defined in the Securities Act. Any discounts or commissions they receive from the selling stockholders and any profits they receive on the resale of the offered securities may be treated as underwriting discounts and commissions under the Securities Act. The selling stockholders will identify any underwriters, agents or dealers and describe their commissions, fees or discounts in the applicable prospectus supplement or pricing supplement, as the case may be.

        The selling stockholders and other persons participating in the sale or distribution of the securities will be subject to applicable prospectus of the Securities Act, and the rules and regulations thereunder, including Regulation M. This regulation may limit the timing of purchases and sales of any of the securities by the selling stockholders or any other person. The anti-manipulation rules under the Securities Act may apply to sales of securities in the market and to the activities of the selling stockholders and any affiliates of the selling stockholders. Furthermore, Regulation M may restrict the ability of any person engaged in the distribution for a period of up to five business days before the distribution. These restrictions may affect the marketability of the securities and the ability of any person or entity to engage in market-making activities with respect to the securities.

        The selling stockholders are not restricted as to the price or prices at which they may sell the securities. Sales of such securities may have an adverse effect on the market price of the securities.

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Moreover, it is possible that a significant number of shares of common stock could be sold at the same time, which may have an adverse effect on the market price of the securities.

        We cannot assure you that the selling stockholder will sell all or any portion of the securities offered hereby.

Underwriters and Agents

        If underwriters are used in a sale, they will acquire the offered securities for their own account. The underwriters may resell the offered securities in one or more transactions, including negotiated transactions. These sales may be made at a fixed public offering price or prices, which may be changed, at market prices prevailing at the time of the sale, at prices related to such prevailing market price or at negotiated prices. The selling stockholders may offer the securities to the public through an underwriting syndicate or through a single underwriter. The underwriters in any particular offering will be mentioned in the applicable prospectus supplement or pricing supplement, as the case may be.

        Unless otherwise specified in connection with any particular offering of securities, the obligations of the underwriters to purchase the offered securities will be subject to certain conditions contained in an underwriting agreement that we and the applicable selling stockholders will enter into with the underwriters at the time of the sale to them. The underwriters will be obligated to purchase all of the securities of the series offered if any of the securities are purchased, unless otherwise specified in connection with any particular offering of securities. Any initial offering price and any discounts or concessions allowed, reallowed or paid to dealers may be changed from time to time.

        The selling stockholders may designate agents to sell the offered securities. Unless otherwise specified in connection with any particular offering of securities, the agents will agree to use their best efforts to solicit purchases for the period of their appointment. The selling stockholders may also sell the offered securities to one or more remarketing firms, acting as principals for their own accounts or as agents for us or any selling stockholders. These firms will remarket the offered securities upon purchasing them in accordance with a redemption or repayment pursuant to the terms of the offered securities. A prospectus supplement or pricing supplement, as the case may be will identify any remarketing firm and will describe the terms of its agreement, if any, with the selling stockholders and its compensation.

        In connection with offerings made through underwriters or agents, the selling stockholders may enter into agreements with such underwriters or agents pursuant to which the selling stockholders receive outstanding securities in consideration for the securities being offered to the public for cash. In connection with these arrangements, the underwriters or agents may also sell securities covered by this prospectus to hedge their positions in these outstanding securities, including in short sale transactions. If so, the underwriters or agents may use the securities received from the selling stockholders under these arrangements to close out any related open borrowings of securities.

Dealers

        The selling stockholders may sell the offered securities to dealers as principals. The selling stockholders may negotiate and pay dealers' commissions, discounts or concessions for their services. The dealer may then resell such securities to the public either at varying prices to be determined by the dealer or at a fixed offering price agreed to with the selling stockholders at the time of resale. Dealers engaged by the selling stockholders may allow other dealers to participate in resales.

Direct Sales

        The selling stockholders may choose to sell the offered securities directly. In this case, no underwriters or agents would be involved.

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Institutional Purchasers

        The selling stockholders may authorize agents, dealers or underwriters to solicit certain institutional investors to purchase offered securities on a delayed delivery basis pursuant to delayed delivery contracts providing for payment and delivery on a specified future date. The applicable prospectus supplement or pricing supplement, as the case may be will provide the details of any such arrangement, including the offering price and commissions payable on the solicitations.

        The selling stockholders will enter into such delayed contracts only with institutional purchasers that the selling stockholders approve. These institutions may include commercial and savings banks, insurance companies, pension funds, investment companies and educational and charitable institutions.

Indemnification; Other Relationships

        The selling stockholders may have agreements with agents, underwriters, dealers and remarketing firms to indemnify them against certain civil liabilities, including liabilities under the Securities Act. Agents, underwriters, dealers and remarketing firms, and their affiliates, may engage in transactions with, or perform services for, the selling stockholders in the ordinary course of business. This includes commercial banking and investment banking transactions.

Market-Making, Stabilization and Other Transactions

        In connection with any offering of common stock, the underwriters may purchase and sell shares of common stock in the open market. These transactions may include short sales, syndicate covering transactions and stabilizing transactions. Short sales involve syndicate sales of common stock in excess of the number of shares to be purchased by the underwriters in the offering, which creates a syndicate short position. "Covered" short sales are sales of shares made in an amount up to the number of shares represented by the underwriters' over-allotment option. In determining the source of shares to close out the covered syndicate short position, the underwriters will consider, among other things, the price of shares available for purchase in the open market as compared to the price at which they may purchase shares through the over-allotment option. Transactions to close out the covered syndicate short involve either purchases of the common stock in the open market after the distribution has been completed or the exercise of the over-allotment option. The underwriters may also make "naked" short sales of shares in excess of the over-allotment option. The underwriters must close out any naked short position by purchasing shares of common stock in the open market. A naked short position is more likely to be created if the underwriters are concerned that there may be downward pressure on the price of the shares in the open market after pricing that could adversely affect investors who purchase in the offering. Stabilizing transactions consist of bids for or purchases of shares in the open market while the offering is in progress for the purpose of pegging, fixing or maintaining the price of the securities.

        In connection with any offering, the underwriters may also engage in penalty bids. Penalty bids permit the underwriters to reclaim a selling concession from a syndicate member when the securities originally sold by the syndicate member are purchased in a syndicate covering transaction to cover syndicate short positions. Stabilizing transactions, syndicate covering transactions and penalty bids may cause the price of the securities to be higher than it would be in the absence of the transactions. The underwriters may, if they commence these transactions, discontinue them at any time.

Fees and Commissions

        In compliance with the guidelines of the Financial Industry Regulatory Authority, Inc. ("FINRA"), the aggregate maximum discount, commission or agency fees or other items constituting underwriting compensation to be received by any FINRA member or independent broker-dealer will not exceed 8% of any offering pursuant to this prospectus and any applicable prospectus supplement or pricing supplement, as the case may be; however, it is anticipated that the maximum commission or discount to be received in any particular offering of securities will be significantly less than this amount.

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LEGAL MATTERS

        Unless otherwise indicated in the applicable prospectus supplement, Skadden, Arps, Slate, Meagher & Flom LLP, New York, New York will provide opinions regarding the authorization and validity of the securities. Skadden, Arps, Slate, Meagher & Flom LLP may also provide opinions regarding certain other matters. Any underwriters will also be advised about legal matters by their own counsel, which will be named in the prospectus supplement.

EXPERTS

        The consolidated financial statements of BankUnited, Inc. and subsidiaries as of December 31, 2012 and 2011, and for each of the years in the three-year period ended December 31, 2012, and management's assessment of the effectiveness of internal control over financial reporting as of December 31, 2012 have been incorporated by reference herein in reliance upon the report of KPMG LLP, independent registered public accounting firm, incorporated by reference herein, and upon the authority of said firm as experts in accounting and auditing.

        The Company acquired Herald National Bank (Herald) during 2012, and management excluded from its assessment of the effectiveness of the Company's internal control over financial reporting as of December 31, 2012, Herald's internal control over financial reporting associated with total assets of $490.5 million and total net interest income of $13.5 million included in the consolidated financial statements of the Company as of and for the year ended December 31, 2012. KPMG LLP's audit of internal control over financial reporting of the Company also excluded an evaluation of the internal control over financial reporting of Herald.

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PART II

INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14.    Other Expenses of Issuance and Distribution.

        The expenses relating to the registration of the securities will be borne by the registrant. Such expenses are estimated to be as follows:

Item 15.    Indemnification of Directors and Officers.

        The DGCL authorizes corporations to limit or eliminate the personal liability of directors to corporations and their stockholders for monetary damages for breaches of directors' fiduciary duties. Our amended and restated certificate of incorporation includes a provision that eliminates the personal liability of directors for monetary damages for breach of fiduciary duty as a director to the fullest extent permitted by Delaware law.

        Section 102(b)(7) of the DGCL permits a corporation to provide in its certificate of incorporation that a director of the corporation shall not be personally liable to the corporation or its stockholders for monetary damages for breach of fiduciary duty as a director, except for liability (i) for any breach of the director's duty of loyalty to the corporation or its stockholders, (ii) for acts or omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (iii) under Section 174 of the DGCL (regarding, among other things, the payment of unlawful dividends or unlawful stock purchases or redemptions), or (iv) for any transaction from which the director derived an improper personal benefit. Our amended and restated certificate of incorporation provide for such limitation of liability.

        Section 145(a) of the DGCL empowers a corporation to indemnify any director, officer, employee or agent, or former director, officer, employee or agent, who was or is a party or is threatened to be made a party to any threatened, pending or completed action, suit or proceeding, whether civil, criminal, administrative or investigative (other than an action by or in the right of the corporation) by reason of such person's service as a director, officer, employee or agent of the corporation, or such person's service, at the corporation's request, as a director, officer, employee or agent of another corporation or enterprise, against expenses (including attorneys' fees), judgments, fines and amounts paid in settlement actually and reasonably incurred by such person in connection with such action, suit or proceeding; provided that such director or officer acted in good faith and in a manner reasonably

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believed to be in or not opposed to the best interests of the corporation, and, with respect to any criminal action or proceeding; provided that such director or officer had no reasonable cause to believe his conduct was unlawful.

        Section 145(b) of the DGCL empowers a corporation to indemnify any person who was or is a party or is threatened to be made a party to any threatened, pending or completed action or suit by or in the right of the corporation to procure a judgment in its favor by reason of the fact that such person is or was a director, officer, employee or agent of the corporation, or is or was serving at the request of the corporation as a director, officer, employee or agent of another enterprise, against expenses (including attorneys' fees) actually and reasonably incurred in connection with the defense or settlement of such action or suit; provided that such director or officer acted in good faith and in a manner he or she reasonably believed to be in or not opposed to the best interests of the corporation, except that no indemnification may be made in respect of any claim, issue or matter as to which such director or officer shall have been adjudged to be liable to the corporation unless and only to the extent that the Delaware Court of Chancery or the court in which such action or suit was brought shall determine upon application that, despite the adjudication of liability but in view of all the circumstances of the case, such director or officer is fairly and reasonably entitled to indemnity for such expenses which the court shall deem proper. Notwithstanding the preceding sentence, except as otherwise provided in the by-laws, we shall be required to indemnify any such person in connection with a proceeding (or part thereof) commenced by such person only if the commencement of such proceeding (or part thereof) by any such person was authorized by our board of directors.

        In addition, our amended and restated certificate of incorporation provide that we must indemnify our directors and officers to the fullest extent authorized by law. Currently, we have entered into separate indemnification agreements with each of our directors and executive officers. Our board of directors also authorized us to enter into, from time to time, additional indemnification agreements with future directors and executive officers. Each indemnification agreement provides, among other things, for indemnification to the fullest extent permitted by law and the Company's amended and restated certificate of incorporation and by-laws against (i) any and all liabilities, expenses, damages, judgments, fines, penalties, ERISA excise taxes, interest and amounts paid in settlement of any claim with the Company's approval and counsel fees and disbursements, (ii) any liability pursuant to a loan guarantee, or otherwise, for any of our indebtedness, and (iii) any liabilities incurred as a result of acting behalf of the Company (as a fiduciary or otherwise) in connection with an employee benefit plan or any related trust or funding mechanism. Each indemnification agreement provides for the advancement or payment of expenses to the indemnitee and for reimbursement to the Company if it is found that such indemnitee is not entitled to such indemnification under applicable law and our amended and restated certificate of incorporation and by-laws. Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers or persons controlling us pursuant to the foregoing provisions, in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

        We are also required to advance certain expenses to our directors and officers and carry directors' and officers' insurance providing indemnification for our directors and officers for some liabilities. We believe that these indemnification provisions and the directors' and officers' insurance are useful to attract and retain qualified directors and executive officers.

Item 16.    Exhibits.

        The Exhibits to this registration statement are listed in the Index to Exhibits on page II-8 and are incorporated by reference herein.

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Item 17.    Undertakings.

        The undersigned registrant hereby undertakes:

        (A)(1)  To file, during any period in which offers or sales are being made, a post-effective amendment to this registration statement:

        (i)    To include any prospectus required by section 10(a)(3) of the Securities Act;

        (ii)   To reflect in the prospectus any facts or events arising after the effective date of the registration statement (or the most recent post-effective amendment thereof) which, individually or in the aggregate, represent a fundamental change in the information set forth in the registration statement. Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering range may be reflected in the form of prospectus filed with the SEC pursuant to Rule 424(b) if, in the aggregate, the changes in volume and price represent no more than 20% change in the maximum aggregate offering price set forth in the "Calculation of Registration Fee" table in the effective registration statement.

        (iii)  To include any material information with respect to the plan of distribution not previously disclosed in the registration statement or any material change to such information in the registration statement;

Provided, however, that paragraphs (A)(1)(i), (A)(1)(ii) and (A)(1)(iii) above do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports filed with or furnished to the SEC by the registrant pursuant to Section 13 or Section 15(d) of the Exchange Act that are incorporated by reference in the registration statement, or is contained in a form of prospectus filed pursuant to Rule 424(b) that is part of the registration statement.

        (2)   That, for the purpose of determining any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

        (3)   To remove from registration by means of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.

        (4)   That, for the purpose of determining liability under the Securities Act to any purchaser:

        A     Each prospectus filed by the registrant pursuant to Rule 424(b)(3) shall be deemed to be part of the registration statement as of the date the filed prospectus was deemed part of and included in the registration statement; and

        B     Each prospectus required to be filed pursuant to Rule 424(b)(2), (b)(5), or (b)(7) as part of a registration statement in reliance on Rule 430B relating to an offering made pursuant to Rule 415(a)(1)(i), (vii), or (x) for the purpose of providing the information required by section 10(a) of the Securities Act shall be deemed to be part of and included in the registration statement as of the earlier of the date such form of prospectus is first used after effectiveness or the date of the first contract of sale of securities in the offering described in the prospectus. As provided in Rule 430B, for liability purposes of the issuer and any person that is at that date an underwriter, such date shall be deemed to be a new effective date of the registration statement relating to the securities in the registration statement to which that prospectus relates, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof. Provided, however, that no statement made in a registration statement or prospectus that is part of the registration

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statement or made in a document incorporated or deemed incorporated by reference into the registration statement or prospectus that is part of the registration statement will, as to a purchaser with a time of contract of sale prior to such effective date, supersede or modify any statement that was made in the registration statement or prospectus that was part of the registration statement or made in any such document immediately prior to such effective date; or

        (5)   That, for the purpose of determining liability of the registrant under the Securities Act to any purchaser in the initial distribution of the securities, the undersigned registrant undertakes that in a primary offering of securities of the undersigned registrant pursuant to this registration statement, regardless of the underwriting method used to sell the securities to the purchaser, if the securities are offered or sold to such purchaser by means of any of the following communications, the undersigned registrant will be a seller to the purchaser and will be considered to offer or sell such securities to such purchaser:

        (i)    Any preliminary prospectus or prospectus of the undersigned registrant relating to the offering required to be filed pursuant to Rule 424;

        (ii)   Any free writing prospectus relating to the offering prepared by or on behalf of the undersigned registrant or used or referred to by the undersigned registrant;

        (iii)  The portion of any other free writing prospectus relating to the offering containing material information about the undersigned registrant or its securities provided by or on behalf of the undersigned registrant; and

        (iv)  Any other communication that is an offer in the offering made by the undersigned registrant to the purchaser.

        (B)  The undersigned registrant hereby undertakes that, for purposes of determining any liability under the Securities Act, each filing of the registrant's annual report pursuant to Section 13(a) or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant to Section 15(d) of the Exchange Act) that is incorporated by reference in the registration statement shall be deemed to be a new registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

        (C)  Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons of the registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that, in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by a director, officer or controlling person of the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, the registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

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SIGNATURES

        Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant certifies that it has reasonable grounds to believe that it meets all the requirements for filing on Form S-3 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Miami Lakes, State of Florida, on the 6th day of March, 2013.

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SIGNATURES AND POWER OF ATTORNEY

        In accordance with the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the dates stated. Each person whose signature appears below constitutes and appoints John A. Kanas, Rajinder P. Singh and Leslie Lunak and each of them severally, as his or her true and lawful attorney-in-fact and agent, each acting along with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any or all amendments (including post-effective amendments) and exhibits to the Registration Statement on Form S-3, and to any registration statement filed under SEC Rule 462, and to file the same, with all exhibits thereto, and all documents in connection therewith, with the SEC, granting unto said attorney-in-fact and agent, full power and authority to do and perform each and every act and thing requisite and necessary to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorney-in-fact and agent, or his or her substitute or substitutes, may lawfully do or cause to be done by virtue hereof.

        Pursuant to the requirements of the Securities Act of 1933, as amended, this Registration Statement has been signed by the following persons in the capacities and on the date indicated.

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EXHIBIT INDEX

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