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As filed with the Securities and Exchange Commission on January 10,24, 2011

Registration No. 333-170203

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

Amendment No. 24
to
FORM S-1
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933

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)

Approximate date of commencement of proposed sale to the public:
As soon as practicable after the effective date of this Registration Statement.

          If any of the securities being registered on this form are to be offered on a delayed or continuous basis pursuant to Rule 415 of the Securities Act of 1933 check the following box. o

          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 post-effective amendment filed pursuant to Rule 462(d) 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

          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 Securities Exchange Act of 1934.

          The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file an amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933 or until this Registration Statement shall become effective on such date as the Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

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The information in this preliminary prospectus is not complete and may be changed. Neither we nor the selling stockholders may sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This preliminary prospectus is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion. Dated January 10,24, 2011

PROSPECTUS

26,250,000 Shares

BankUnited, Inc.

Common Stock

        This is the initial public offering of our common stock. We are offering 4,000,000 shares of our common stock. The selling stockholders identified in this prospectus are offering an additional 22,250,000 shares. We will not receive any of the proceeds from the sale of the shares being sold by the selling stockholders.

        Prior to this offering there has been no public market for our common stock. It is currently estimated that the public offering price per share of our common stock will be between $$23.00 and $$25.00 per share. We intend to apply to list ourOur common stock has been approved for listing on the New York Stock Exchange under the symbol "BKU."

        See "Risk Factors" on page 13 to read about factors you should consider before buying our common stock.

        Neither the Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

        To the extent that the underwriters sell more than 26,250,000 shares of our common stock, the underwriters have the option to purchase up to an additional 3,937,500 shares of our common stock from the selling stockholders at the initial public offering price less the underwriting discount, within 30 days from the date of this prospectus, to cover over-allotments.

        The underwriters expect to deliver the shares of our common stock against payment in New York, New York on                        , 2011.

Prospectus dated                        , 2011

        We, the selling stockholders and the underwriters have not authorized anyone to provide any information other than that contained in this prospectus or in any free writing prospectus prepared by or on behalf of us or to which we have referred you. We, the selling stockholders and the underwriters take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. We are not, and the selling stockholders and underwriters are not, making an offer of these securities in any jurisdiction where the offer is not permitted. You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front of this prospectus.

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        The shares of our common stock that you purchase in this offering will not be a bank deposit and will not be insured or guaranteed by the FDIC or any other government agency. Your investment will be subject to investment risk, and you must be capable of affording the loss of your entire investment.

        For investors outside the United States: None of we, the selling stockholders or any of the underwriters have done anything that would permit this offering or possession or distribution of this prospectus in any jurisdiction where action for that purpose is required, other than in the United States. You are required to inform yourselves about and to observe any restrictions relating to this offering and the distribution of this prospectus.

MARKET AND INDUSTRY DATA AND FORECASTS

        This prospectus includes market and industry data and forecasts that we have developed from independent research firms, publicly available information, various industry publications, other

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published industry sources or our internal data and estimates. Independent research reports, industry publications and other published industry sources generally indicate that the information contained therein was obtained from sources believed to be reliable, but do not guarantee the accuracy and completeness of such information. Although we believe that the publications and reports are reliable, none of we, the selling stockholders or the underwriters have independently verified the data. Our internal data, estimates and forecasts are based on information obtained from our investors, trade and business organizations and other contacts in the markets in which we operate and our management's understanding of industry conditions. Although we believe that such information is reliable, we have not had such information verified by any independent sources.

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PROSPECTUS SUMMARY

        This summary highlights selected information contained elsewhere in this prospectus. This summary may not contain all of the information that you should consider before investing in our common stock. You should read the entire prospectus carefully, including the section entitled "Risk Factors," our financial statements and the related notes thereto and management's discussion and analysis thereof included elsewhere in this prospectus, before making an investment decision to purchase our common stock. Unless we state otherwise or the context otherwise requires, references in this prospectus to "we," "our," "us," and the "Company" for all periods subsequent to the Acquisition (as defined below) refer to BankUnited, Inc., a Delaware corporation, and its consolidated subsidiaries. References in this prospectus to "BankUnited" and the "Bank" for all periods beginning May 22, 2009 refer to BankUnited, a federal savings association, formed to acquire substantially all of the assets (including loans, employees and certain operations), and assume all of the non-brokered deposits and substantially all other liabilities, of the Failed Bank (as defined below).

BankUnited, Inc.

Summary

        BankUnited, Inc. is a savings and loan holding company with two wholly-owned subsidiaries: BankUnited, which is one of the largest independent depository institutions headquartered in Florida by assets, and BankUnited Investment Services, Inc., or BankUnited Investment Services, a Florida insurance agency which provides comprehensive wealth management products and financial planning services. BankUnited is a federally-chartered, federally-insured savings association headquartered in Miami Lakes, Florida, with $11.2 billion of assets, more than 1,100 professionals and 78 branches in 13 counties at September 30, 2010. Our goal is to build a premier, large 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 financial services to both our commercial and consumer customers, who are predominantly located in Florida.

        BankUnited, Inc. was organized by a management team led by our Chairman, President and Chief Executive Officer, John A. Kanas, on April 28, 2009 and was initially capitalized with $945.0 million by a group of investors. On May 21, 2009, BankUnited was granted a savings association charter and the newly formed bank acquired substantially all of the assets and assumed all of the non-brokered deposits and substantially all other liabilities of BankUnited, FSB, or the Failed Bank, from the Federal Deposit Insurance Corporation, or the FDIC, in a transaction which we refer to as the Acquisition. Concurrently with the Acquisition, we entered into two loss sharing agreements, or the Loss Sharing Agreements, which cover certain legacy assets, including the entire legacy loan portfolio and other real estate owned, or OREO, and certain purchased investment securities, including private-label mortgage-backed securities and non-investment grade securities. We refer to assets covered by the Loss Sharing Agreements as Covered Assets (or, in certain cases, Covered Loans or Covered Securities).

        Since the Bank's establishment in May 2009, we have pursued our new strategy and as part of this strategy we have recruited a new executive management team, substantially enhanced our middle management team, redesigned the Bank's underwriting functions, and have begun the process of improving the Bank's information technology systems and optimizing our existing branch network. For the nine months ended September 30, 2010, the Company was one of the most profitable and well-capitalized bank holding companies in the United States, having earned 1.9% on its average assets and 17.7% on its average common stockholder's equity, and achieved a 41.9% efficiency ratio. BankUnited's tier 1 leverage ratio was 10.1% and its tier 1 risk-based capital ratio was 42.5% at September 30, 2010. The Company's tangible common equity ratio was 10.7% at September 30, 2010.

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We intend to invest our excess capital to grow opportunistically both organically and through acquisitions.

        Our management team is led by Mr. Kanas, a veteran of the banking industry who built North Fork Bancorporation, or North Fork, into a leading regional bank based in New York. At the time of its sale to Capital One Financial Corporation, or Capital One, in December 2006, North Fork was one of the top 25 bank holding companies in the United States. Mr. Kanas served as the Chairman of North Fork from 1986 to 2006 and President and Chief Executive Officer of North Fork from 1977 to 2006. Through organic growth and over 15 acquisitions, Mr. Kanas oversaw the growth and expansion of North Fork from less than $1 billion in assets in 1977 to nearly $60 billion in assets by 2006. According to FactSet Research Systems, while for the five-year period prior to its sale to Capital One, North Fork generated a total annualized return of 11.2%, which equaled the median total annualized return of the top fifty U.S. bank holding companies (excluding North Fork) by assets, for the ten-year period, North Fork generated a total annualized return of 20.5%, compared to a median total annualized return of 14.5%. North Fork distinguished itself as one of the most efficient banking companies in the United States through Mr. Kanas' vision of safe and prudent expansion, cost control and capital management. North Fork was sold to Capital One in December 2006 for $13.2 billion, or 4.0 times tangible equity, a transaction multiple higher than both the median transaction multiple of 3.2 for sales of banks with assets between $10 billion and $30 billion and the median transaction multiple of 3.0 for sales in the banking industry during the period from 2000 to 2006.

The Acquisition

        On May 21, 2009, BankUnited entered into a purchase and assumption agreement, or the Purchase and Assumption Agreement, with the FDIC, Receiver of the Failed Bank, to acquire substantially all of the assets and assume all of the non-brokered deposits and substantially all other liabilities of the Failed Bank. Excluding the effects of acquisition accounting adjustments, BankUnited acquired $13.6 billion of assets and assumed $12.8 billion of liabilities. The fair value of the assets acquired was $10.9 billion and the fair value of the liabilities assumed was $13.1 billion. BankUnited received a net cash consideration from the FDIC in the amount of $2.2 billion.

        The Acquisition consisted of assets with a fair value of $10.9 billion, including $5.0 billion of loans (with a corresponding unpaid principal balance, or UPB, of $11.2 billion), a $3.4 billion FDIC indemnification asset, $538.9 million of investment securities, $1.2 billion of cash and cash equivalents, $177.7 million of foreclosed assets, $243.3 million of Federal Home Loan Bank, or FHLB, stock and $347.4 million of other assets. Liabilities with a fair value of $13.1 billion were also assumed, including $8.3 billion of non-brokered deposits, $4.6 billion of FHLB advances, and $112.2 million of other liabilities.

        Concurrently with the Acquisition, the Bank entered into the Loss Sharing Agreements with the FDIC that cover certain legacy assets, including the entire loan portfolio and OREO, and certain purchased investment securities, including private-label mortgage-backed securities and non-investment grade securities. The Bank acquired other BankUnited, FSB assets that are not covered by the Loss Sharing Agreements with the FDIC including cash, certain investment securities purchased at fair market value and other tangible assets. The Loss Sharing Agreements do not apply to subsequently acquired, purchased or originated assets. At September 30, 2010, the Covered Assets consisted of assets with a book value of $4.3 billion. The total UPB (or, for investment securities, unamortized cost basis) of the Covered Assets at September 30, 2010 was $8.9 billion.

        Pursuant to the terms of the Loss Sharing Agreements, the Covered Assets are subject to a stated loss threshold whereby the FDIC will reimburse the Bank for 80% of losses up to the $4.0 billion stated threshold and 95% of losses in excess of the $4.0 billion stated threshold, calculated, in each case, based on UPB (or, for investment securities, unamortized cost basis) plus certain interest and

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expenses. The carrying value of the FDIC indemnification asset at September 30, 2010 was $2.7 billion. The Bank will reimburse the FDIC for its share of recoveries with respect to losses for which the FDIC paid the Bank a reimbursement under the Loss Sharing Agreements. The FDIC's obligation to reimburse the Company for losses with respect to the Covered Assets began with the first dollar of loss incurred. We have received $997.2 million from the FDIC in reimbursements under the Loss Sharing Agreements for claims filed for losses incurred as of September 30, 2010. See "Business—The Acquisition—Loss Sharing Agreements."

        Several elements of our Acquisition are favorable relative to other FDIC-assisted transactions and position the Company to generate significant value. At the time of the Acquisition, bank failures were on the rise and the U.S. Treasury's unprecedented Supervisory Capital Assessment Program for the largest U.S. bank holding companies was underway. Due in part to the distress in the banking system, economic uncertainty and poor capital markets conditions, the Covered Loans and OREO were purchased by the Bank in a bidding process for 76.5% of their $11.4 billion in UPB as of the Acquisition date, which represented the fair market value for those assets at that time. The discount was one of the largest relative to other FDIC-assisted transactions and reflected, in addition to the abovementioned factors, the poor quality of the assets acquired as noted by the ratio of non-performing assets to total assets of 23.5% at May 21, 2009. In addition, our bid included the granting of a warrant to the FDIC, allowing the FDIC to participate in the economic upside of the transaction if certain performance levels are achieved. Along with the pricing terms, the Loss Sharing Agreements and the size of the transaction enable the Company to generate significant capital even in severe loss scenarios. For example, in the worst case scenario of a 100% credit loss on all Covered Loans and OREO, we would recover no less than 89.7% of the UPB as of the Acquisition date, assuming compliance with the terms of the Loss Sharing Agreements.

        Furthermore, the Loss Sharing Agreements include attractive provisions that optimize our flexibility and reduce our risk associated with the Covered Assets, including the following:

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Ability to sell loans.  We may sell up to 2.5% of the Covered Loans based on the UPB at Acquisition, or approximately $280.0 million, on an annual basis without prior consent of the FDIC. Any losses incurred from such loan sales are covered under the Loss Sharing Agreements.



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No residual credit risk.  We have the right to sell any or all of the Covered Assets at the termination date of our Loss Sharing Agreements, and any losses incurred will be covered. This allows us to crystallize any residual loss that would otherwise materialize after the expiration of the Loss Sharing Agreements.



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Certain securities covered.  Certain private-label mortgage-backed securities purchased in the Acquisition are covered under the Loss Sharing Agreements.



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Enhanced flexibility to execute corporate strategy opportunistically.  The Bank has the ability to pursue certain strategic transactions including, after an 18-month lock-up period from the Acquisition date, this offering.

        We view our relationship with the FDIC as a long-term partnership in which both parties are economically aligned to minimize credit losses on the Covered Assets.

Our Competitive Strengths

        We believe that we are especially well positioned to create value for our stockholders.

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Experienced and respected management team with a successful track record.  Our management team is led by Mr. Kanas, who has attracted an entirely new executive management team and enhanced our middle management team with seasoned professionals with significant banking

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experience and a history of high performance at nationally recognized mid- to large-cap financial institutions. Many of our management team members have extensive experience working together at North Fork and have successfully executed operating business models similar to ours in the past. In addition, our management has a successful track record of growing bank franchises both organically and through acquisitions.

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Strong and reliable revenue.  A majority of BankUnited's revenue is currently derived from assets that are covered by the Loss Sharing Agreements. For the nine months ended September 30, 2010, the Company earned 1.9% on its average assets and 17.7% on its average common stockholder's equity, both of which were among the leading ratios in the U.S. banking industry.



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Limited credit risk exposure for Covered Assets.  At September 30, 2010, the Covered Assets were being carried at a book value of $4.3 billion and the total UPB (or, for investment securities, unamortized cost basis) of the Covered Assets was $8.9 billion. Since the Bank's current estimate of cumulative losses on the Covered Assets of approximately $4.8 billion exceeds the $4.0 billion stated loss threshold in the Loss Sharing Agreements, 95% of any incremental credit losses above our current estimates attributable to the Covered Assets would be absorbed by the FDIC and 5% of the losses would be absorbed by the Bank under the Loss Sharing Agreements.



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Robust capital position.  At September 30, 2010, BankUnited was one of the most well-capitalized banks in the United States, affording it the financial flexibility to pursue growth opportunities and pay dividends. We had a 10.7% tangible common equity ratio, and the Bank had a 10.1% tier 1 leverage ratio and a 42.5% tier 1 risk-based ratio. We declared quarterly dividends of $14.0 million on September 17 and December 9, 2010. In addition, on October 19, 2010, we declared a special one-time dividend of $6.0 million.



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Ideally situated for growth and expansion.  We believe we are extremely well positioned for growth. The banking industry in our markets, Florida and the southeastern United States, is significantly distressed. We believe this distress will give us opportunities to acquire other institutions and attract talented bankers and customers from competing banks. Our strong capital position and generation, as well as scalable operating system, should allow us to take advantage of these opportunities.



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New high-capacity operating platform.  Since May 2009, we have made significant investments in our infrastructure and technology in order to create a scalable platform for future organic and non-organic growth. We are in the midst of converting to a new core deposit system that has significant capacity and delivers comprehensive commercial and consumer products and services. We have made other significant investments in financial reporting and servicing systems. We believe we are creating a technology platform that will allow us to compete effectively with large regional banking institutions.

Risks We Face

        There are a number of risks that you should consider before buying our common stock. These risks are discussed more fully in the section entitled "Risk Factors" beginning on page 13. These risks include, but are not limited to:

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Failure to comply with the terms of our Loss Sharing Agreements with the FDIC may result in significant losses;



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The geographic concentration of our markets in the coastal regions of Florida makes our business highly susceptible to local economic conditions and natural disasters;



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Delinquencies and defaults in residential mortgages have recently increased, creating a backlog in courts and an increase in the amount of legislative action that might restrict or delay our

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ability to foreclose and hence delay the collection of payments for single family residential loans under the Loss Sharing Agreements; and

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The enactment of the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 may have a material effect on our operations.

Our Business

        Our primary business is to offer a full range of traditional banking products and financial services coupled with high-touch, personalized customer service to both our commercial and consumer customers, who are predominantly located in Florida. We offer a full array of lending products to cater to our customers' needs, including, but not limited to, small business loans, commercial real estate loans, equipment loans, term loans, asset-backed loans, letters of credit, commercial lines of credit, residential mortgage loans, home equity and consumer loans. We also offer traditional depository products, including checking accounts, money market deposit accounts, savings accounts and certificates of deposit, repo products and cash management services. Through dedicated financial consultants and licensed bankers, BankUnited Investment Services provides comprehensive wealth management products and services, including mutual funds, annuities, life insurance, individual securities and succession, estate and financial planning services. We believe that our customers are attracted to us because we offer the resources and sophistication of a large bank as well as the responsiveness and relationship-based approach of a community bank.

Our Market Area

        We view our market as the southeast region of the United States with a current focus on Florida, and in particular the Miami metropolitan statistical area, or MSA. We believe Florida represents a long-term attractive banking market. According to estimates from SNL Financial, from June 30, 2000 to June 30, 2010, Florida added 2.9 million new residents, the third most of any U.S. state, and, at June 30, 2010, had a total population of 18.9 million and a median household income of $49,910. Additionally, the state has 1.9 million active businesses. We believe Florida's population provides tremendous opportunities for us to grow our business. At June 30, 2010, BankUnited ranked 11^th in deposit market share in Florida and 6^th in the Miami MSA, according to SNL Financial.

        Florida's economy and banking industry continue to face significant challenges. Since 2007, many Florida banks have experienced capital constraints and liquidity challenges as a result of significant losses from loans with poor credit quality and investments that have had sizeable decreases in value or realized losses. The undercapitalization and increased regulation of the banking sector have caused many banks to reduce lending to new and existing clients and focus primarily on improving their balance sheets, putting pressure on commercial borrowers to look for new banking relationships. As of September 30, 2010, 40 banks with $31.8 billion in assets have failed since 2008 in Florida. Given our competitive strengths, including an experienced management team, robust capital position and scalable platform, we believe these challenges present significant acquisition and organic growth opportunities for us.

        Over time, we will look to expand our branch network outside of Florida in selected markets such as New York, where our management team has had significant experience and has the competitive advantage of having managed one of the most successful regional banks in that market. However, for a limited period of time, certain of our executive officers are subject to non-compete agreements which may restrict them from operating in New York, New Jersey and Connecticut.

Our Business Strategy

        Since the Acquisition, we have focused on the financial needs of small and medium sized businesses and consumers throughout Florida. Through BankUnited, we deliver a comprehensive range

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of traditional depository and lending products, online services and cash management tools for businesses. We also offer on a national basis commercial lease financing services and municipal leasing services. Through our non-bank subsidiary, BankUnited Investment Services, we offer a suite of products including mutual funds, annuities, life insurance, individual securities and other wealth management services.

        Our goal is to build a premier, large regional bank in attractive growth markets, employing the following key elements:

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Transformation to relationship banking.  Since the Acquisition, our primary strategic objective has been to transform the Bank from a price-driven, transaction-based, mortgage lender to a service-driven, relationship-based, business-focused bank. We have taken an active approach to accomplish this transformation, including:



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Recruitment of top talent.  The entire management leadership team and a large majority of the next tier of management have been replaced with top performers who were recruited nationally. We have also hired teams of relationship bankers from regional competitors. Furthermore, given BankUnited's strong capital levels and expansion strategy, we believe we have an opportunity to continue hiring and developing talent for the foreseeable future.



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Shift of culture towards building relationships.  We emphasize winning relationships rather than gathering accounts. As such, we have implemented new compensation practices that properly align our employees with our strategic vision by rewarding long-term profitability instead of volume, exited the broker business and focused on building long-term relationships with small business customers.



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Investment in physical infrastructure.  In addition to our investment in people, we have been enhancing and optimizing both our facilities and branch network. We have focused on eliminating non-strategic branches and facilities, consolidated most of our non-branch operations into one location and improved the overall presentation and infrastructure of our resulting footprint.



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Improvement of our technology platform.  We are committed to building a technology infrastructure that enables us to deliver best-in-class products and services to our clients and is also scalable to accommodate our long-term growth plans. As such, we have made and are continuing to make significant investments in our information technology infrastructure, including a conversion to a more robust core deposit platform that is scheduled for completion in early 2011.

With the changes implemented as discussed above, we have increased our core deposits (defined as total deposits less certificates of deposit, or CDs) since the Acquisition to September 30, 2010 from $2.1 billion to $3.8 billion and lowered our cost of deposits (excluding the impact of accretion from fair value adjustments due to acquisition accounting) from 3.5% to 1.6%. In addition, since the Acquisition to September 30, 2010, we have generated $429.5 million of new commercial and commercial real estate loan commitments.

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Multi-faceted expansion plan.  We intend to geographically expand our franchise and reinvest our excess capital by hiring talented producers, openingde novo branches and acquiring complementary businesses. These expansion strategies complement our overall strategic vision.



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Hire talented producers.  A key component to expanding our franchise footprint is to opportunistically hire talented individuals or teams with relationships in commercial banking, small business banking or our other primary business lines. For example, since the Acquisition to September 30, 2010, we have hired 31 lenders from various regional competitors.

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Open de novo branches.  As part of our strategy to broaden our branch network, BankUnited plans to expand into new markets and to broaden its footprint. We plan to open new branches and consolidate certain existing branches with those in more desirable locations within the same market. In 2009, we consolidated 9 branches and in 2010, we opened 2 new branches and currently have 7 branches under development, which will allow us to, among other things, expand our presence in Tampa and enter the Orlando market.



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Acquire complementary businesses.  We believe significant opportunities exist for additional expansion through acquisitions both in our current market and in other markets within the United States with similar characteristics. Our acquisition strategy includes FDIC-assisted transactions, traditional whole bank acquisitions and complementary acquisitions of select banking and banking-related businesses. For example, we recently acquired two leasing businesses, which serve as the platform for our ability to provide commercial financing services on a national basis.



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Build a scalable and efficient operating model.  Our management team has a history of running highly efficient banking institutions and is focused on building a culture of expense control. Furthermore, we have made and intend to continue to make significant investments in our information technology systems to position us for future growth. For the nine months ended September 30, 2010, the Company's efficiency ratio was 41.9%, which compares favorably with other U.S. banks.



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Maintain strong regulatory relationships.  We believe that maintaining strong relationships with regulators is an important element of any bank strategy. As such, we maintain an active dialogue with our primary regulators. Additionally, we view our relationship with the FDIC as a long-term partnership in which both parties are economically aligned to minimize credit losses on the Covered Assets. We continually collaborate with the FDIC to develop and implement new loss mitigation strategies for the Covered Assets. We have received $997.2 million from the FDIC in reimbursements under the Loss Sharing Agreements for claims filed for losses incurred as of September 30, 2010.

Additional 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.

Reorganization

        We are currently a direct, wholly-owned subsidiary of BU Financial Holdings LLC, or the LLC, a Delaware limited liability company, and whose common equity interests are referred to herein as units. Prior to the completion of this offering, we will effect a reorganization so that our investors, our named executive officers and all other members of the LLC will hold equity interests in us directly rather than indirectly through the LLC. Immediately prior to the consummation of this offering, the LLC will be liquidated and all interests in the registrant, BankUnited, Inc., a Delaware corporation, will be distributed to the members of the LLC in accordance with its amended and restated limited liability company agreement dated as of May 21, 2009, or the LLC Agreement. There are currently 36 holders of units in the LLC. All of the transactions necessary to effect the liquidation are collectively referred to herein as the "Reorganization." For additional information, see "Compensation Discussion and Analysis—Executive Officer Compensation—Equity-Based Compensation."

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The Offering

        References in this section to the number of shares of our common stock to be outstanding after this offering are based on 92,971,850 shares of our common stock outstanding and excludesas of January 10, 2011. Such references exclude:

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981,710 shares of our common stock issuable upon exercise of outstanding stock options at a weighted average exercise price of $$17.04 per share (of which 113,451 shares are issuable upon exercise of vested stock options) as of January 10, 2011; and



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7,500,000 shares of common stock reserved for issuance, and not subject to outstanding options, under our benefit plans, in each case asthe BankUnited, Inc. 2010 Omnibus Equity Incentive Plan.

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        Unless otherwise indicated, the information presented in this prospectus:

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gives effect to a 10-for-1 common stock split, which was effected on January 10, 2011;



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assumes an initial public offering price of $$24.00 per share, the midpoint of the price range set forth on the cover of this prospectus;

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assumes that the underwriters' option to purchase additional shares of our common stock from the selling stockholders to cover over-allotments, if any, is not exercised;



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gives effect to the reorganization transactions that will be completed in connection with this offering (see the section entitled "Reorganization"), including the transactions with respect to profits interest units, or PIUs, in the LLC described under "Compensation Discussion and Analysis—Executive Officer Compensation—Equity-Based Compensation;" and



•

for purposes of the number or weighted average of shares of common stock outstanding only, assumes that the warrant issued to the FDIC in connection with the Acquisition is redeemed in cash pursuant to the terms thereof.

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Summary Historical Consolidated Financial Data

        You should read the summary historical consolidated financial information set forth below in conjunction with "Management's Discussion and Analysis of Financial Condition and Results of Operations," "Capitalization" and the consolidated financial statements and the related notes thereto included elsewhere in this prospectus. The summary historical consolidated financial information set forth below at and for the nine months ended September 30, 2010 is derived from our unaudited interim condensed consolidated financial statements included elsewhere in this prospectus and includes all adjustments (consisting of normal recurring adjustments) that we considered necessary for a fair presentation of the financial position and the results of operations for these periods. Operating results for the nine months ended September 30, 2010 are not necessarily indicative of the results that may be expected for the year ended December 31, 2010. The summary historical consolidated financial information set forth below at December 31, 2009 and for the period from April 28, 2009 (date of inception) to December 31, 2009 has been derived from our audited consolidated financial statements included elsewhere in this prospectus. The summary historical consolidated financial information set forth below for each of the periods from October 1, 2008 to May 21, 2009 and at and for the fiscal years ended September 30, 2008 and 2007 has been derived from the audited consolidated financial statements of the Failed Bank included elsewhere in this prospectus.

        Although we were incorporated on April 28, 2009, neither we nor the Bank had any substantive operations prior to the Acquisition on May 21, 2009. Results of operations of the Company for the post-Acquisition periods are not comparable to the results of operations of the Failed Bank for the pre-Acquisition periods. Results of operations for the post-Acquisition periods reflect, among other things, the acquisition method of accounting. See "Management's Discussion and Analysis of Financial Condition and Results of Operations—Periods Presented and Factors Affecting Comparability."

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        A $1.00 increase (decrease) in the assumed initial public offering price of $$24.00 per share would increase (decrease) additional cash and cash equivalents, total assets and total stockholder's equity by $$3.8 million, assuming that the number of shares offered by us, as set forth on the cover of this prospectus, remains the same and after deducting estimated underwriting discounts and commissions and offering expenses.

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RISK FACTORS

        Investing in our common stock involves a high degree of risk. You should carefully consider the following risk factors, as well as all of the other information contained in this prospectus including our consolidated financial statements and the related notes thereto, before deciding to invest in our common stock. The occurrence of any of the following risks could materially and adversely affect our business, prospects, financial condition, results of operations and cash flow. In such case, the trading price of our common stock could decline and you could lose all or part of your investment.

Risks Related to Our Business

Failure to comply with the terms of our Loss Sharing Agreements with the FDIC may result in significant losses.

        In May 2009, we purchased substantially all of the assets and assumed all of the non-brokered deposits and substantially all other liabilities of the Failed Bank in an FDIC-assisted transaction, and presently a substantial portion of BankUnited's revenue is derived from such assets. The purchased loans, commitments, foreclosed assets and certain securities are covered by the Loss Sharing Agreements with the FDIC, which provide that a significant portion of the losses related to the Covered Assets will be borne by the FDIC. Under the Loss Sharing Agreements, we are obligated to comply with certain loan servicing standards, including requirements to participate in government-sponsored loan modification programs. As these standards evolve, we may experience difficulties in complying with the requirements of the Loss Sharing Agreements, which could result in Covered Assets losing some or all of their coverage. BankUnited is subject to audits with the terms of the Loss Sharing Agreements by the FDIC through its designated agent. The required terms of the agreements are extensive and failure to comply with any of the guidelines could result in a specific asset or group of assets losing their loss sharing coverage. See "Business—The Acquisition—Loss Sharing Agreements."

The geographic concentration of our markets in the coastal regions of Florida makes our business highly susceptible to local economic conditions and natural disasters.

        Unlike larger financial institutions that are more geographically diversified, our branch offices are primarily concentrated in the coastal regions of Florida. Additionally, a significant portion of our loans secured by real estate are secured by commercial and residential properties in Florida. The Florida economy and our market in particular have been affected by the downturn in commercial and residential property values, and the decline in real estate values in Florida during the downturn has been higher than the national average. Additionally, the Florida economy relies heavily on tourism and seasonal residents, which have also been affected by recent market disruptions. Continued deterioration in economic conditions in the markets we serve or the occurrence of a natural disaster, such as a hurricane, or a man-made catastrophe, such as the Gulf of Mexico oil spill, could result in one or more of the following:

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an increase in loan delinquencies;



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an increase in problem assets and foreclosures;



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a decrease in the demand for our products and services; or



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a decrease in the value of collateral for loans, especially real estate, in turn reducing customers' borrowing power, the value of assets associated with problem loans and collateral coverage.

        Hurricanes and other catastrophes to which our markets in the coastal regions of Florida are susceptible also can disrupt our operations, result in damage to our properties, reduce or destroy the value of collateral and negatively affect the local economies in which we operate, which could have a material adverse effect on our results of operations.

        A decline in existing and new real estate sales decreases lending opportunities, may delay the collection of our cash flow from the Loss Sharing Agreements, and negatively affects our income. We

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do not anticipate that the real estate market will improve in the near-term and, accordingly, this could lead to additional valuation adjustments on our loan portfolios.

Delinquencies and defaults in residential mortgages have recently increased, creating a backlog in courts and an increase in the amount of legislative action that might restrict or delay our ability to foreclose and hence delay the collection of payments for single family residential loans under the Loss Sharing Agreements.

        For the single family residential loans covered by the Loss Sharing Agreements, we cannot collect loss share payments until we liquidate the properties securing those loans. These loss share payments could be delayed by an extended foreclosure process, including delays resulting from a court backlog, local or national foreclosure moratoriums or other delays, and these delays could have a material adverse effect on our results of operations. Home ownerHomeowner protection laws may also delay the initiation or completion of foreclosure proceedings on specified types of residential mortgage loans. Any such limitations are likely to cause delayed or reduced collections from mortgagors. Any restriction on our ability to foreclose on a loan, any requirement that we forgo a portion of the amount otherwise due on a loan or any requirement that we modify any original loan terms could negatively impact our business, financial condition, liquidity and results of operations.

Our loan portfolio has and will continue to be affected by the ongoing correction in residential and commercial real estate prices and reduced levels of residential and commercial real estate sales.

        Soft residential and commercial real estate markets, higher delinquency and default rates, and increasingly volatile and constrained secondary credit markets have affected the mortgage industry generally, and Florida in particular, which is where our business is currently most heavily concentrated. Our financial results may be adversely affected by changes in real estate values. We make credit and reserve decisions based on the current conditions of borrowers or projects combined with our expectations for the future. If the slowdown in the real estate market continues, we could experience higher charge-offs and delinquencies beyond that which is provided in the allowance for loan losses. Although we have the Loss Sharing Agreements with the FDIC, these agreements do not cover 100% of the losses attributable to Covered Assets. In addition, the Loss Sharing Agreements will not mitigate any losses on our non-Covered Assets and our earnings could be adversely affected through a higher than anticipated provision for loan losses on such assets.

Our business is highly susceptible to credit risk on our non-Covered Assets.

        As a lender, we are exposed to the risk that our customers will be unable to repay their loans according to their terms and that the collateral securing the payment of their loans (if any) may not be sufficient to assure repayment. Similarly, we have credit risk embedded in our securities portfolio. Our credit standards, procedures and policies may not prevent us from incurring substantial credit losses, particularly in light of market developments in recent years. Recent economic and market developments and the potential for continued economic disruption present considerable risks to us and it is difficult to determine the depth and duration of the economic and financial market problems and the many ways in which they may impact our business in general. The Loss Sharing Agreements only cover certain legacy assets, and credit losses on assets not covered by the Loss Sharing Agreements could have a material adverse effect on our operating results.

Changes in interest rates could have an adverse impact on our results of operations and financial condition.

        Our earnings and cash flows depend to a great extent upon the level of our net interest income. Changes in interest rates can increase or decrease our net interest income, because different types of assets and liabilities may react differently, and at different times, to market interest rate changes. Net interest income is the difference between the interest income we earn on loans, investments and other interest earning assets, and the interest we pay on interest bearing liabilities, such as deposits and borrowings. When interest bearing liabilities mature or reprice more quickly than interest earning assets

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in a period, an increase in interest rates could reduce net interest income. Similarly, when interest earning assets mature or reprice more quickly than interest bearing liabilities, falling interest rates could reduce net interest income. Additionally, an increase in interest rates may, among other things, reduce the demand for loans and our ability to originate loans and decrease loan repayment rates. A decrease in the general level of interest rates may affect us through, among other things, increased prepayments on our loan and mortgage-backed securities portfolios and increased competition for deposits. Accordingly, changes in the level of market interest rates affect our net yield on interest earning assets, loan origination volume, loan and mortgage-backed securities portfolios, and our overall results. Interest rates are highly sensitive to many factors beyond our control, including general economic conditions and policies of various governmental and regulatory agencies, particularly the Federal Reserve.

        We attempt to manage our risk from changes in market interest rates by adjusting the rates, maturity, repricing, and balances of the different types of interest-earning assets and interest bearing liabilities; however, interest rate risk management techniques are not precise, and we may not be able to successfully manage our interest rate risk. As a result, a rapid increase or decrease in interest rates could have an adverse effect on our net interest margin and results of operations.

We depend on our executive officers and key personnel to continue the implementation of our long-term business strategy and could be harmed by the loss of their services.

        We believe that our continued growth and future success will depend in large part on the skills of our senior management team. We believe our senior management team possesses valuable knowledge about and experience in the banking industry and that their knowledge and relationships would be very difficult to replicate. Although our senior management team has entered into employment agreements with us, they may not complete the term of their employment agreements or renew them upon expiration. Our success also depends on the experience of our branch managers and lending officers and on their relationships with the customers and communities they serve. The loss of service of one or more of our executive officers or key personnel, or the inability to recruit and retain qualified personnel in the future, could have an adverse effect on our business, financial condition or operating results and the value of our common stock.

Our allowance for credit losses may not be adequate to cover actual credit losses.

        We maintain an allowance for loan losses that represents management's estimate of probable losses inherent in our credit portfolio. This estimate requires management to make certain assumptions and involves a high degree of judgment, particularly as our originated loan portfolio is not yet seasoned and has not yet developed an observable loss trend and Covered Loans that did not exhibit evidence of deterioration in credit quality at acquisition, or non-ACI loans, have limited delinquency statistics. Management considers numerous factors, including, but not limited to, internal risk ratings, loss forecasts, collateral values, geographic location, borrower FICO scores, delinquency rates, the proportion of non-performing and restructured loans in the loan portfolio, origination channels, product mix, underwriting practices, industry conditions, economic trends and net charge-off trends.

        If management's assumptions and judgments prove to be incorrect, our current allowance may be insufficient and we may be required to increase our allowance for loan losses. In addition, federal and state regulators periodically review our allowance for loan losses and may require us to increase our provision for loan losses or recognize further loan charge-offs, based on judgments different than those of our management. Continued adverse economic conditions could make management's estimate even more complex and difficult to determine. Any increase in our allowance for loan losses will result in a decrease in net income and capital and could have a material adverse effect on our financial condition and results of operations. See "Management's Discussion and Analysis of Financial Condition and Results of Operations—Analysis of the Allowance for Loan Losses" and "Management's Discussion

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and Analysis of Financial Condition and Results of Operations—Critical Accounting Policies and Estimates—Accounting for Covered Loans."

We may not be able to find suitable acquisition candidates and may be unable to manage our growth due to acquisitions.

        A key component of our growth strategy is to pursue acquisitions of complementary businesses. As consolidation of the banking industry continues, the competition for suitable acquisition candidates may increase. We compete with other banking companies for acquisition opportunities and there are a limited number of candidates that meet our acquisition criteria. Consequently, we may not be able to identify suitable candidates for acquisitions. If we are unable to locate suitable acquisition candidates willing to sell on terms acceptable to us, our net income could decline and we would be required to find other methods to grow our business.

        Even if suitable candidates are identified and we succeed in consummating future acquisitions, acquisitions involve risks that the acquired business may not achieve anticipated revenue, earnings or cash flows. There may also be unforeseen liabilities relating to the acquired institution or arising out of the acquisition, asset quality problems of the acquired entity, difficulty operating in markets in which we have had no or only limited experience and other conditions not within our control, such as adverse personnel relations, loss of customers because of change in identity, and deterioration in local economic conditions.

        In addition, the process of integrating acquired entities will divert significant management time and resources. We may not be able to integrate successfully or operate profitably any financial institutions we may acquire. We may experience disruption and incur unexpected expenses in integrating acquisitions. Any acquisitions we do make may not enhance our cash flows, business, financial condition, results of operations or prospects and may have an adverse effect on our results of operations, particularly during periods in which the acquisitions are being integrated into our operations.

We face significant competition from other financial institutions and financial services providers, which may decrease our growth or profits.

        The primary market we serve is Florida. Consumer and commercial banking in Florida is highly competitive. Our market contains not only a large number of community and regional banks, but also a significant presence of the country's largest commercial banks. We compete with other state and national financial institutions located in Florida and adjoining states as well as savings and loan associations, savings banks and credit unions for deposits and loans. In addition, we compete with financial intermediaries, such as consumer finance companies, mortgage banking companies, insurance companies, securities firms, mutual funds and several government agencies as well as major retailers, all actively engaged in providing various types of loans and other financial services.

        The financial services industry could become even more competitive as a result of legislative, regulatory and technological changes and continued consolidation. Banks, securities firms and insurance companies can merge under the umbrella of a financial holding company, which can offer virtually any type of financial service, including banking, securities underwriting, insurance (both agency and underwriting) and merchant banking. Increased competition among financial services companies due to the recent consolidation of certain competing financial institutions may adversely affect our ability to market our products and services. Also, technology has lowered barriers to entry and made it possible for banks to compete in our market without a retail footprint by offering competitive rates, as well as non-banks to offer products and services traditionally provided by banks. Many of our competitors have fewer regulatory constraints and may have lower cost structures. Additionally, due to their size, many competitors may offer a broader range of products and services as well as better pricing for certain products and services than we can.

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        Our ability to compete successfully depends on a number of factors, including:

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the ability to develop, maintain and build upon long-term customer relationships based on quality service, high ethical standards and safe and sound assets;



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the ability to attract and retain qualified employees to operate our business effectively;



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the ability to expand our market position;



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the scope, relevance and pricing of products and services offered to meet customer needs and demands;



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the rate at which we introduce new products and services relative to our competitors;



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customer satisfaction with our level of service; and



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industry and general economic trends.

        Failure to perform in any of these areas could significantly weaken our competitive position, which could adversely affect our growth and profitability, which, in turn, could harm our business, financial condition and results of operations.

Since we engage in lending secured by real estate and may be forced to foreclose on the collateral property and own the underlying real estate, we may be subject to the increased costs and risks associated with the ownership of real property, which could have an adverse effect on our business or results of operations.

        A significant portion of our loan portfolio is secured by real property. During the ordinary course of business, we may foreclose on and take title to properties securing certain loans, in which case, we are exposed to the risks inherent in the ownership of real estate. The amount that we, as a mortgagee, may realize after a default is dependent upon factors outside of our control, including:

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general or local economic conditions;



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environmental cleanup liability;



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neighborhood values;



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interest rates;



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real estate tax rates;



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operating expenses of the mortgaged properties;



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supply of and demand for rental units or properties;



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ability to obtain and maintain adequate occupancy of the properties;



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zoning laws;



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governmental rules, regulations and fiscal policies; and



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hurricanes or other natural or man-made disasters.

        Certain expenditures associated with the ownership of real estate, principally real estate taxes and maintenance costs, may also adversely affect our operating expenses.

We are dependent on our information technology and telecommunications systems and third-party servicers, and systems failures, interruptions or breaches of security could have an adverse effect on our financial condition and results of operations.

        Our business is highly dependent on the successful and uninterrupted functioning of our information technology and telecommunications systems and third-party servicers. We outsource our major systems including our electronic funds transfer, or EFT, transaction processing, cash management and online banking services. We rely on these systems to process new and renewal loans, gather deposits, provide customer service, facilitate collections and share data across our organization. The failure of these systems, or the termination of a third-party software license or service agreement on

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which any of these systems is based, could interrupt our operations. Because our information technology and telecommunications systems interface with and depend on third-party systems, we could experience service denials if demand for such services exceeds capacity or such third-party systems fail or experience interruptions. If sustained or repeated, a system failure or service denial could result in a deterioration of our ability to process new and renewal loans, gather deposits and provide customer service, compromise our ability to operate effectively, damage our reputation, result in a loss of customer business, and/or subject us to additional regulatory scrutiny and possible financial liability, any of which could have a material adverse effect on our financial condition and results of operations.

        We are currently in the process of implementing substantial changes to our core deposit platform. We may not be able to successfully implement this new core system in an effective manner. In addition, we may incur significant increases in costs and encounter extensive delays in the implementation and rollout of our new operating system. If there are technological impediments, unforeseen complications, errors or breakdowns in implementing this new core operating system or if this new core operating system does not meet the requirements of our customers, our business, financial condition, results of operations or customer perceptions may be adversely affected.

        In addition, we provide our customers the ability to bank remotely, including online and over the telephone. The secure transmission of confidential information over the Internet and other remote channels is a critical element of remote banking. Our network could be vulnerable to unauthorized access, computer viruses, phishing schemes and other security breaches. We may be required to spend significant capital and other resources to protect against the threat of security breaches and computer viruses, or to alleviate problems caused by security breaches or viruses. To the extent that our activities or the activities of our customers involve the storage and transmission of confidential information, security breaches and viruses could expose us to claims, litigation and other possible liabilities. Any inability to prevent security breaches or computer viruses could also cause existing customers to lose confidence in our systems and could adversely affect our reputation and our ability to generate business.

BankUnited is a de novo bank, which could be mistaken for the Failed Bank, and this and other reputational risks could affect our results.

        BankUnited was established as ade novo federal savings association in order to participate in the FDIC-assisted acquisition of the Failed Bank. There is a reputational risk in being incorrectly associated with the Failed Bank. Our ability to originate and maintain accounts is highly dependent upon consumer and other external perceptions of our business practices and/or our financial health. Adverse perceptions regarding our business practices and/or our financial health could damage our reputation in both the customer and funding markets, leading to difficulties in generating and maintaining accounts as well as in financing them. Adverse developments with respect to the consumer or other external perceptions regarding the practices of our competitors, or our industry as a whole, may also adversely impact our reputation. In addition, adverse reputational impacts on third parties with whom we have important relationships may also adversely impact our reputation. Adverse reputational impacts or events may also increase our litigation risk. We carefully monitor internal and external developments for areas of potential reputational risk and have established governance structures to assist in evaluating such risks in our business practices and decisions.

Three material weaknesses were identified in the first audit period following the Acquisition. Existing or future material weaknesses in our internal controls, if not properly corrected, could result in material misstatements in our financial statements.

        We are not yet required to comply with Section 404 of the Sarbanes-Oxley Act of 2002, or to make an assessment of the effectiveness of our internal control over financial reporting under the Sarbanes-Oxley Act of 2002. Furthermore, our independent auditors have not been engaged to express, nor have they expressed, an opinion on the effectiveness of our internal control over financial reporting in

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accordance with Sarbanes-Oxley Act of 2002. However, in connection with the audit of our consolidated financial statements for the period from May 22, 2009 through December 31, 2009, which we refer to as the period ended or ending December 31, 2009, we identified three material weaknesses in our system of internal control over financial reporting. A material weakness is a deficiency, or combination of deficiencies in internal controls over financial reporting, that results in a reasonable possibility that a material misstatement of our annual or interim financial statements will not be prevented or detected on a timely basis.

        The first material weakness identified relates to the fact that management did not design effective controls over its loan modeling process in order to account for certain loans in accordance with the requirements of Accounting Standards Codification, or ASC, Subtopic 310-30,Loans and Debt Securities Acquired with Deteriorated Credit Quality. A material weakness existed due to the fact that the design of internal control did not provide for an independent review or approval and validation of the loan cash flow model and related assumptions. In addition, the design of internal control over the loan cash flow model did not provide for adequate access, change management, and end-user computing controls including spreadsheets. Furthermore, management's controls were not designed to reflect on a timely basis the impact of changes in market conditions on the loan cash flow model and related assumptions. The second material weakness relates to the fact that management did not maintain effective internal controls over the valuation and resulting writedown to fair market value of OREO properties. Specifically, a material weakness existed due to the fact that the control over the timely recording of OREO values by the Collateral Valuation Department in the Company's sub-ledger system was not operating effectively. The third material weakness relates to the fact that BankUnited did not design effective controls over its financial reporting process in order to ascertain the complete, accurate, and timely preparation of its consolidated financial statements, including the applicable disclosures and footnotes, or design effective review controls to provide for proper accounting of nonroutine transactions. A material weakness existed due to the fact that the design of internal control did not provide for a comprehensive review of interim financial information and the consolidated financial statements to ensure the completeness and accuracy of information supporting various financial statement components.

        Steps we are taking to address the identified material weaknesses may not be sufficient to remediate the identified material weaknesses or prevent additional material weaknesses from occurring. If we fail to remediate the material weaknesses or if additional material weaknesses are discovered in the future, we may fail to meet our future reporting obligations and our financial statements may contain material misstatements. Any such failure could also adversely affect the results of the periodic management evaluations and annual auditor attestation reports regarding the effectiveness of our internal controls over financial reporting, and could negatively impact our business, results of operations and reputation.

BankUnited Investment Services offers third-party products including mutual funds, annuities, life insurance, individual securities and other wealth management services which could experience significant declines in value subjecting us to reputational damage and litigation risk.

        Through our subsidiary BankUnited Investment Services, we offer third-party products including mutual funds, annuities, life insurance, individual securities and other wealth management products and services. If these products do not generate competitive risk-adjusted returns that satisfy clients in a variety of asset classes, we will have difficulty maintaining existing business and attracting new business. Additionally, our investment services businesses involve the risk that clients or others may sue us, claiming that we have failed to perform under a contract or otherwise failed to carry out a duty owed to them. Our investment services businesses are particularly subject to this risk and this risk may be heightened during periods when credit, equity or other financial markets are deteriorating in value or are particularly volatile, or when clients or investors are experiencing losses. Significant declines in the performance of these third-party products could subject us to reputational damage and litigation risk.

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Risks Relating to the Regulation of Our Industry

The enactment of the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010 may have a material effect on our operations.

        On July 21, 2010, President Obama signed into law the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, or the Dodd-Frank Act, which imposes significant regulatory and compliance changes. The key effects of the Dodd-Frank Act on our business are:

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changes to the thrift supervisory structure;



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changes to regulatory capital requirements;



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creation of new government regulatory agencies;



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limitation on federal preemption;



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changes in insured depository institution regulations; and



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mortgage loan origination and risk retention.

        The changes resulting from the Dodd-Frank Act may impact the profitability of our business activities, require changes to certain of our business practices, impose upon us more stringent capital, liquidity and leverage requirements or otherwise adversely affect our business. These changes may also require us to invest significant management attention and resources to evaluate and make any changes necessary to comply with new statutory and regulatory requirements. Failure to comply with the new requirements or with any future changes in laws or regulations may negatively impact our results of operations and financial condition. For a more detailed description of the Dodd-Frank Act, see "Regulation and Supervision—The Dodd-Frank Act."

We operate in a highly regulated environment and the laws and regulations that govern our operations, corporate governance, executive compensation and accounting principles, or changes in them, or our failure to comply with them, may adversely affect us.

        We are subject to extensive regulation, supervision, and legislation that govern almost all aspects of our operations. Intended to protect customers, depositors and deposit insurance funds, these laws and regulations, among other matters, prescribe minimum capital requirements, impose limitations on the business activities in which we can engage, limit the dividend or distributions that BankUnited can pay to us, restrict the ability of institutions to guarantee our debt, and impose certain specific accounting requirements on us that may be more restrictive and may result in greater or earlier charges to earnings or reductions in our capital than generally accepted accounting principles. Compliance with laws and regulations can be difficult and costly, and changes to laws and regulations often impose additional compliance costs. Our failure to comply with these laws and regulations, even if the failure follows good faith effort or reflects a difference in interpretation, could subject us to restrictions on our business activities, fines and other penalties, any of which could adversely affect our results of operations, capital base and the price of our securities. Further, any new laws, rules and regulations could make compliance more difficult or expensive or otherwise adversely affect our business and financial condition.

        In addition, as a public company, we will incur significant legal, accounting, insurance and other expenses. Compliance with other rules of the United States Securities and Exchange Commission, or the SEC, and the rules of the stock exchange on which our common stock is listed will increase our legal and financial compliance costs and make some activities more time consuming and costly.

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The FDIC's restoration plan and the related increased assessment rate could adversely affect our earnings.

        Market developments have significantly depleted the deposit insurance fund, or DIF, of the FDIC and reduced the ratio of reserves to insured deposits. As a result of recent economic conditions and the enactment of the Dodd-Frank Act, the FDIC has increased the deposit insurance assessment rates and thus raised deposit premiums for insured depository institutions. If these increases are insufficient for the DIF to meet its funding requirements, further special assessments or increases in deposit insurance premiums may be required. We are generally unable to control the amount of premiums that we are required to pay for FDIC insurance. If there are additional bank or financial institution failures, we may be required to pay even higher FDIC premiums than the recently increased levels. Any future additional assessments, increases or required prepayments in FDIC insurance premiums may materially adversely affect results of operations.

Federal banking agencies periodically conduct examinations of our business, including compliance with laws and regulations, and our failure to comply with any supervisory actions to which we are or become subject as a result of such examinations may adversely affect us.

        Federal banking agencies, including the Office of Thrift Supervision, or OTS, periodically conduct examinations of our business, including compliance with laws and regulations. If, as a result of an examination, a federal banking agency were to determine that the financial condition, capital resources, asset quality, earnings prospects, management, liquidity or other aspects of any of our operations had become unsatisfactory, or that the Company or its management was in violation of any law or regulation, it may take a number of different remedial actions as it deems appropriate. These actions include the power to enjoin "unsafe or unsound" practices, to require affirmative actions to correct any conditions resulting from any violation or practice, to issue an administrative order that can be judicially enforced, to direct an increase in BankUnited's capital, to restrict our growth, to assess civil monetary penalties against our officers or directors, to remove officers and directors and, if it is concluded that such conditions cannot be corrected or there is an imminent risk of loss to depositors, to terminate BankUnited's deposit insurance. If we become subject to such regulatory actions, our business, results of operations and reputation may be negatively impacted.

Many of our new activities and expansion plans require regulatory approvals, and failure to obtain them may restrict our growth.

        We intend to complement and expand our business by pursuing strategic acquisitions of banks and other financial institutions. We must generally receive federal regulatory approval before we can acquire an institution or business. In determining whether to approve a proposed acquisition, federal bank regulators will consider, among other factors, the effect of the acquisition on the competition, our financial condition, and our future prospects. The regulators also review current and projected capital ratios and levels, the competence, experience, and integrity of management and its record of compliance with laws and regulations, the convenience and needs of the communities to be served (including the acquiring institution's record of compliance under the Community Reinvestment Act, or CRA) and the effectiveness of the acquiring institution in combating money laundering activities. Such regulatory approvals may not be granted on terms that are acceptable to us, or at all. We may also be required to sell branches as a condition to receiving regulatory approval, which condition may not be acceptable to us or, if acceptable to us, may reduce the benefit of any acquisition.

        In addition to the acquisition of existing financial institutions, as opportunities arise, we plan to continuede novo branching as a part of our internal growth strategy and possibly enter into new markets throughde novo branching.De novo branching and any acquisition carries with it numerous risks, including the inability to obtain all required regulatory approvals. The failure to obtain these regulatory approvals for potential future strategic acquisitions andde novo branches may impact our business plans and restrict our growth.

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Financial institutions, such as BankUnited, face a risk of noncompliance and enforcement action with the Bank Secrecy Act and other anti-money laundering statutes and regulations.

        The federal Bank Secrecy Act, the USA PATRIOT Act, and other laws and regulations require financial institutions, among other duties, to institute and maintain an effective anti-money laundering program and file suspicious activity and currency transaction reports as appropriate. The federal Financial Crimes Enforcement Network, established by the U.S. Treasury Department to administer the Bank Secrecy Act, is authorized to impose significant civil money penalties for violations of those requirements, and has recently engaged in coordinated enforcement efforts with the individual federal banking regulators, as well as the U.S. Department of Justice, Drug Enforcement Administration, and Internal Revenue Service. There is also increased scrutiny of compliance with the rules enforced by the Office of Foreign Assets Control.

        In order to comply with regulations, guidelines and examination procedures in this area, we have enhanced our anti-money laundering program by adopting new policies and procedures and selecting a new, robust automated anti-money laundering software solution that is scheduled to be implemented in early 2011. If our policies, procedures and systems are deemed deficient or the policies, procedures and systems of the financial institutions that we have already acquired or may acquire in the future are deficient, we would be subject to liability, including fines and regulatory actions such as restrictions on our ability to pay dividends and the necessity to obtain regulatory approvals to proceed with certain aspects of our business plan, including our acquisition plans.

We are subject to the CRA and fair lending laws, and failure to comply with these laws could lead to material penalties.

        The CRA, the Equal Credit Opportunity Act, the Fair Housing Act and other fair lending laws and regulations impose nondiscriminatory lending requirements on financial institutions. The Department of Justice and other federal agencies are responsible for enforcing these laws and regulations. A successful challenge to an institution's performance under the CRA or fair lending laws and regulations could result in a wide variety of sanctions, including the required payment of damages and civil money penalties, injunctive relief, imposition of restrictions on mergers and acquisitions activity, and restrictions on expansion activity. Private parties may also have the ability to challenge an institution's performance under fair lending laws in private class action litigation.

Risks Related to this Offering and Ownership of Our Common Stock

There is no prior public market for our common stock and one may not develop.

        Prior to this offering, there has not been a public trading market for our common stock. An active trading market may not develop or be sustained after this offering. If an active trading market does not develop, you may have difficulty selling your shares of common stock at an attractive price, or at all. The initial public offering price for our common stock sold in this offering will be determined by negotiations among us, the selling stockholders and the underwriters. This price may not be indicative of the price at which our common stock will trade after this offering. The market price of our common stock may decline below the initial offering price, and you may not be able to sell your common stock at or above the price you paid in this offering, or at all.

Our stock price may be volatile, and you could lose all or part of your investment as a result.

        You should consider an investment in our common stock to be risky, and you should invest in our common stock only if you can withstand a significant loss and wide fluctuation in the market value of your investment. The market price of our common stock could be subject to wide fluctuations in

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response to, among other things, the factors described in this "Risk Factors" section, and other factors, some of which are beyond our control. These factors include:

•

quarterly variations in our results of operations or the quarterly financial results of companies perceived to be similar to us;



•

changes in expectations as to our future financial performance, including financial estimates by securities analysts and investors;



•

our announcements or our competitors' announcements regarding new products or services, enhancements, significant contracts, acquisitions or strategic investments;



•

fluctuations in the market valuations of companies perceived by investors to be comparable to us;



•

future sales of our common stock;



•

additions or departures of members of our senior management or other key personnel;



•

changes in industry conditions or perceptions; and



•

changes in applicable laws, rules or regulations and other dynamics.

        Furthermore, the stock markets have experienced price and volume fluctuations that have affected and continue to affect the market price of equity securities of many companies. These fluctuations have often been unrelated or disproportionate to the operating performance of these companies. These broad market fluctuations, as well as general economic, systemic, political and market conditions, such as recessions, loss of investor confidence, interest rate changes, or international currency fluctuations, may negatively affect the market price of our common stock.

        If any of the foregoing occurs, it could cause our stock price to fall and may expose us to securities class action litigation that, even if unsuccessful, could be costly to defend and a distraction to management.

We may not pay cash dividends on our common stock.

        Although we intend to pay dividends to our stockholders, we have no obligation to do so and may change our dividend policy at any time without notice to our stockholders. Holders of our common stock are only entitled to receive such cash dividends as our Board may declare out of funds legally available for such payments. Any decision to declare and pay dividends will be dependent on a variety of factors, including our financial condition, earnings, legal requirements and other factors that our Board deems relevant. In addition, our ability to pay dividends may be limited by covenants of any future indebtedness we or our subsidiaries incur. As a result, you many not receive any return on an investment in our common stock unless you sell our common stock for a price greater than that which you paid for it. In addition, since we are a holding company with no significant assets other than the capital stock of our banking subsidiary, we will need to depend upon dividends from the Bank for substantially all of our income. Accordingly, our ability to pay dividends depends primarily upon the receipt of dividends or other capital distributions from the Bank. The Bank's ability to pay dividends to us is subject to, among other things, its earnings, financial condition and need for funds, as well as federal and state governmental policies and regulations applicable to us and the Bank, which limit the amount that may be paid as dividends without prior regulatory approval.

You will incur immediate and substantial dilution in the net tangible book value of the shares you purchase in this offering.

        The initial public offering price is likely to be substantially higher than the net tangible book value per share of our common stock based on the total value of our tangible assets less our total liabilities

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divided by our shares of common stock outstanding immediately following this offering. Therefore, if you purchase common stock in this offering, you will experience immediate and substantial dilution in net tangible book per share value after completion of this offering. To the extent outstanding options to purchase our common stock are exercised, there will be further dilution. See the section entitled "Dilution."

Our stock price could decline due to the large number of outstanding shares of our common stock eligible for future sale.

        Sales of substantial amounts of our common stock in the public market following this offering, or the perception that these sales could occur, could cause the market price of our common stock to decline. These sales could also make it more difficult for us to sell equity or equity relatedequity-related securities in the future, at a time and place that we deem appropriate.

        Upon completion of this offering, we will have 96,971,850 outstanding shares of common stock, assuming no exercise of the underwriters' over-allotment option, and an initial public offering price of $            per share, the midpoint of the price range set forth on the cover of this prospectus.stock. Of the outstanding shares, all of the 26,250,000 shares sold in this offering plus any additional(30,187,500 shares sold uponif the underwriters exercise of the underwriters'in full their over-allotment optionoption) will be freely tradable, except that any shares purchased by "affiliates" (as that term is defined in Rule 144 under the Securities Act of 1933, or the Securities Act), only may be sold in compliance with the limitations described in the section entitled "Shares Eligible For Future Sale—Rule 144." Taking into consideration the effect of the lock-up agreements described below and the provisions of Rule 144 and Rule 701 ofunder the Securities Act, the remaining shares of our common stock willmay may be availableeligible for saleresale in the public market as follows:

•

shares will be eligible for sale onunder Rule 144 under the date of this prospectus; and



•

shares will be eligible for sale upon the expiration of the lock-up agreements described below.

        We, our executive officers, directors and the selling stockholders have agreed with the underwriters, subject to certain exceptions, not to dispose of or hedge any of their shares of common stock or securities convertible into or exchangeable for shares during the period from the date of this prospectus continuing through the date 180 days after the date of this prospectus, except with the prior written consent of Morgan Stanley & Co. Incorporated and Merrill Lynch, Pierce, Fenner & Smith Incorporated. See the section entitled "Underwriters." In addition, (1) each of Mr. Kanas and certain funds affiliated with Blackstone, Carlyle, Centerbridge and WL Ross have separately agreed during the 18 months from the date of this prospectus and (2) our other executive officers have separately agreed during the 12 months from the date of this prospectus not to effect any sales pursuant to Rule 144 under the Securities Act of any of our equity securities. See "Description of Our Capital Stock—Registration Rights." Any future sales of common stock by our executive officers will further be subject to minimum equity ownership requirements to which our executive officers have agreed. See "Compensation Discussion and Analysis—Executive Officer Compensation—Equity Ownership Requirements."

        In addition, we intend to file a registration statement on Form S-8 under the Securities Act to register an aggregate of approximately 8.5 million shares of common stock for issuance under our 2009 Stock Option Plan and 2010 Omnibus Equity Incentive Plan. We may issue all of these shares without any action or approval by our stockholders, and these shares once issued (including upon exercise of outstanding options) will be available for sale into the public market subject to the restrictions described above, if applicable to the holder. Any shares issued in connection with acquisitions, the exercise of stock options or otherwise would dilute the percentage ownership held by investors who purchase our shares in this offering.

"Anti-takeover" provisions and the regulations to which we are subject may make it more difficult for a third party to acquire control of us, even if the change in control would be beneficial to stockholders.

        We are a savings and loan holding company incorporated in the state of Delaware. Anti-takeover provisions in Delaware law and our certificate of incorporation and by-laws, as well as regulatory approvals that would be required under federal law, could make it more difficult for a third-party to

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take control of us and may prevent stockholders from receiving a premium for their shares of our common stock. These provisions could adversely affect the market price of our common stock and could reduce the amount that stockholders might get if we are sold.

        Our certificate of incorporation will provide for, among other things:

•

advance notice for nomination of directors and other stockholder proposals;



•

the removal of directors by stockholders for cause only;



•

limitations on the ability of stockholders to call a special meeting of stockholders;



•

a prohibition of stockholder action by written consent;

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•

the approval by a super-majority of outstanding shares to amend certain provisions of the by-laws and the certificate of incorporation; and



•

the authorization of "blank check" preferred stock with such designations, rights and preferences as may be determined from time to time by our Board.

        Delaware law also imposes some restrictions on mergers and other business combinations between us and any holder of 15% or more of our outstanding common stock. See the section entitled "Description of Our Capital Stock—Anti-Takeover Considerations and Special Provisions of our Certificate of Incorporation, By-Laws and Delaware Law." We believe that these provisions protect our stockholders from coercive or otherwise unfair takeover tactics by requiring potential acquirers to negotiate with our Board and by providing our Board with more time to assess any acquisition proposal. However, these provisions apply even if the offer may be determined to be beneficial by some stockholders and could delay or prevent an acquisition that our Board determines is not in our best interest and that of our stockholders.

        Furthermore, banking laws impose notice, approval and ongoing regulatory requirements on any shareholder or other party that seeks to acquire direct or indirect "control" of an FDIC-insured depository institution. These laws include the Savings and Loan Holding Company Act, the Bank Holding Company Act of 1956 and the Change in Bank Control Act. These laws could delay or prevent an acquisition.

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

        Some of the statements under "Prospectus Summary," "Risk Factors," "Management's Discussion and Analysis of Financial Condition and Results of Operations," "Business" and elsewhere in this prospectus may contain forward-looking statements that reflect our current views with respect to, among other things, future events and financial performance. We generally identify forward-looking statements by terminology such as "outlook," "believes," "expects," "potential," "continues," "may," "will," "could," "should," "seeks," "approximately," "predicts," "intends," "plans," "estimates," "anticipates" or the negative version of those words or other comparable words. Any forward-looking statements contained in this prospectus are based on the historical performance of us and our subsidiaries or on our current plans, estimates and expectations. The inclusion of this forward-looking information should not be regarded as a representation by us, the underwriters or any other person that the future plans, estimates or expectations contemplated by us will be achieved. Such forward-looking statements are subject to various risks and uncertainties and assumptions relating to our 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 our underlying assumptions prove to be incorrect, our actual results may vary materially from those indicated in these statements. These factors should not be construed as exhaustive and should be read in conjunction with the other cautionary statements that are included elsewhere in this prospectus. We do not undertake any obligation to publicly update or review any forward-looking statement, whether as a result of new information, future developments or otherwise. 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, those factors described in "Risk Factors" and "Management's Discussion and Analysis of Financial Condition and Results of Operations."

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REORGANIZATION

        We are currently a direct, wholly-owned subsidiary of the LLC. Prior to the completion of this offering, we will effect reorganization so that our investors, our named executive officers and all other members of the LLC will hold equity interests in us directly rather than indirectly through the LLC.

        Immediately prior to the consummation of this offering, the LLC will be liquidated and all interests in the registrant, BankUnited, Inc. will be distributed to the members of the LLC in accordance with its LLC Agreement. Following this liquidation, BankUnited, Inc. will be the ultimate parent entity of the group and will have two wholly-owned subsidiaries: BankUnited and BankUnited Investment Services. There are currently 36 holders of units in the LLC. All of the transactions necessary to effect the liquidation are collectively referred to herein as the "Reorganization."

        For additional information, see "Compensation Discussion and Analysis—Executive Officer Compensation—Equity-Based Compensation."

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        The following diagram shows our organizational structure, including our principal subsidiaries only, prior to giving effect to the Reorganization:

Pre-Reorganization

                 Immediately after the consummation of this offering and after the completion of the Reorganization, the following diagram shows our organization structure, including our principal subsidiaries only:

Post-Reorganization and IPO

(1)

Percentages exclude impact of PIUs.

(2)

Includes impact of PIUs, based on an assumed initial offering price of $24.00 per share, the midpoint of the price range set forth on the cover of this prospectus.

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USE OF PROCEEDS

        We estimate that the net proceeds to us from the sale of our common stock in this offering will be $$86.2 million, at an assumed initial public offering price of $$24.00 per share, the midpoint of the price range set forth on the cover of this prospectus, and after deducting estimated underwriting discounts and commissions and offering expenses. Each $1.00 increase (decrease) in the assumed initial public offering price of $$24.00 per share, the midpoint of the price range set forth on the cover of this prospectus, would increase (decrease) the net proceeds to us of this offering by $$3.8 million, assuming the number of shares offered by us, as set forth on the cover of this prospectus, remains the same and after deducting estimated underwriting discounts and commissions and offering expenses. We will not receive any proceeds from the sale of shares of our common stock by the selling stockholders. We intend to use the net proceeds of this offering for general corporate purposes.

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DIVIDEND POLICY

        We initially anticipate paying a quarterly dividend of $$0.14 per share on our common stock, subject to the discretion of our Board and dependent on, among other things, our financial condition, results of operations, capital requirements, restrictions contained in future financing instruments and other factors that our Board may deem relevant. Dividends from the Bank are the principal source of funds for the payment of dividends on our common stock. The Bank is subject to certain restrictions that may limit its ability to pay dividends to us. See "Regulation and Supervision—Regulatory Limits on Dividends and Distributions." During the period ended December 31, 2009, we did not pay a cash dividend to the holder of our common stock. On October 28, 2010, we paid a quarterly dividend of $14.0 million, with a record date of October 15, 2010. On October 28, 2010, we also paid a one-time special dividend of $6.0 million, with a record date of October 19, 2010. On December 9, 2010, we declared another quarterly dividend of $14.0 million, with a record date of January 3, 2011, which will be paid on January 18, 2011.

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CAPITALIZATION

        The following table sets forth our cash and cash equivalents and our capitalization at September 30, 2010:

•

on an actual basis; and



•

on an as adjusted basis to give effect to the sale of shares of common stock in this offering at an assumed initial public offering price of $$24.00 per share, the midpoint of the price range on the cover of this prospectus, after deducting estimated underwriting discounts and commissions and offering expenses as if it had occurred on September 30, 2010.2010 and our amended and restated certificate of incorporation, which will become effective in connection with the consummation of this offering.

        This table should be read in conjunction with "Selected Historical Consolidated Financial Information," "Management's Discussion and Analysis of Financial Condition and Results of Operations" and the consolidated financial statements and the related notes thereto appearing elsewhere in this prospectus.

        A $1.00 increase (decrease) in the assumed initial public offering price of $$24.00 per share would increase (decrease) total stockholder's equity and total capitalization by $$3.8 million, assuming that the number of shares offered by us, as set forth on the cover of this prospectus, remains the same and after deducting estimated underwriting discounts and commissions and offering expenses.

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DILUTION

        If you invest in our common stock, your ownership interest will be diluted to the extent of the difference between the initial public offering price per share of our common stock and the as adjusted net tangible book value per share of our common stock upon consummation of this offering. Our historical net tangible book value at September 30, 2010 was $1.2 billion, or $12.71 per share of common stock based on the 92,971,850 shares issued and outstanding as of such date. Net tangible book value per share represents the book value of our total tangible assets less the book value of our total liabilities divided by the number of shares of common stock then issued and outstanding.

        After giving effect to our sale of 4,000,000 shares of common stock at an assumed initial public offering price of $$24.00 per share, the midpoint of the price range on the cover of this prospectus, and after deducting estimated underwriting discounts and commissions and offering expenses, our as adjusted net tangible book value at September 30, 2010 would have been $             million,$1.3 billion, or $$13.08 per share. This amount represents an immediate increase in net tangible book value to our existing stockholders of $$0.37 per share and an immediate dilution to new investors of $$10.92 per share.

        The following table illustrates this per share dilution:

        Each $1.00 increase (decrease) in the assumed initial public offering price of $$24.00 per share would increase (decrease) our as adjusted net tangible book value by approximately $$3.8 million, or approximately $$0.04 per share, and the pro forma dilution per share to investors in this offering by approximately $$0.96 per share, assuming that the number of shares offered by us, as set forth on the cover of this prospectus, remains the same and after deducting estimated underwriting discounts and commissions and offering expenses. The number of shares offered by us in this offering may be increased or decreased from the number of shares on the cover page of this prospectus. Each increase (decrease) of 1.0 million shares in the number of shares offered by us would increase (decrease) our as adjusted net tangible book value by approximately $$22.8 million, or approximately $$0.10 per share, and the pro forma dilution per share to investors in this offering by approximately $$0.10 per share, assuming the assumed initial public offering price per share of $$24.00 per share, the midpoint of the price range on the cover of this prospectus, remains the same and after deducting estimated underwriting discounts and commissions and offering expenses. The as adjusted information discussed above is illustrative only and will adjust based on the actual initial public offering price and other terms of this offering determined at pricing.

        If the underwriters exercise their option to purchase additional shares of our common stock in full in this offering, the net tangible book value per share after this offering would not change since the shares for this option are all being provided by our selling stockholders and we will not receive any of the proceeds from the sale of these shares.

        The following table summarizes at September 30, 2010 the average price per share paid by our existing stockholders and by investors participating in this offering, based on an assumed initial public

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offering price of $$24.00 per share, the midpoint of the price range on the cover of this prospectus, and before deducting estimated underwriting discounts and commissions and offering expenses.

        Assuming no exercise of the over-allotment option, sales of shares of common stock by the selling stockholders in this offering will reduce the number of shares of common stock held by existing stockholders to ,70,721,850, or approximately %72.9% of the total shares of common stock outstanding after this offering, and will increase the number of shares held by new investors to ,26,250,000, or approximately %27.1% of the total shares of common stock outstanding after this offering. If the underwriters exercise their over-allotment option in full, the number of shares held by existing stockholders will be reduced to 66,784,350 shares, or %68.9% of the total shares outstanding, and the number of shares held by investors participating in this offering will be increased to 30,187,500 shares, or %31.1% of the total shares outstanding.

        The above discussion and tables excludes 981,710 shares of our common stock issuable upon the exercise of outstanding stock options at a weighted average exercise price of $$17.04 per share (of which 113,451 shares are issuable upon exercise of vested stock options) as of January 10, 2011 and 7,500,000 shares of common stock reserved for issuance, and not subject to outstanding options, under our benefit plans in each case as of                        , 2011.the BankUnited, Inc. 2010 Omnibus Equity Incentive Plan. To the extent any of the foregoing options are exercised, there will be further dilution to investors participating in this offering.

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SELECTED HISTORICAL CONSOLIDATED FINANCIAL INFORMATION

        You should read the selected historical consolidated financial information set forth below in conjunction with "Management's Discussion and Analysis of Financial Condition and Results of Operations," "Capitalization" and the consolidated financial statements and the related notes thereto included elsewhere in this prospectus. The selected historical consolidated financial information set forth below at and for the nine months ended September 30, 2010 is derived from our unaudited interim condensed consolidated financial statements included elsewhere in this prospectus and includes all adjustments (consisting of normal recurring adjustments) that we considered necessary for a fair presentation of the financial position and the results of operations for these periods. Operating results for the nine months ended September 30, 2010 are not necessarily indicative of the results that may be expected for the year ended December 31, 2010. The selected historical consolidated financial information set forth below at December 31, 2009 and for the period from April 28, 2009 (date of inception) to December 31, 2009 has been derived from our audited consolidated financial statements included elsewhere in this prospectus. The selected historical consolidated financial information set forth below at September 30, 2008 and 2007, for each of the periods from October 1, 2008 to May 21, 2009 and for the fiscal years ended September 30, 2008 and 2007 has been derived from the audited consolidated financial statements of the Failed Bank included elsewhere in this prospectus. The selected historical consolidated financial information set forth below at and for the fiscal years ended September 30, 2006 and 2005 has been derived from the unaudited consolidated financial statements of the Failed Bank not included in this prospectus.

        Although we were incorporated on April 28, 2009, neither we nor the Bank had any substantive operations prior to the Acquisition on May 21, 2009. Results of operations of the Company for the post-Acquisition periods are not comparable to the results of operations of the Failed Bank for the pre-Acquisition periods. Results of operations for the post-Acquisition periods reflect, among other things, the acquisition method of accounting. See "Management's Discussion and Analysis of Financial Condition and Results of Operations—Periods Presented and Factors Affecting Comparability."

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        Management of the Company believes this non-GAAP financial measure provides an additional meaningful method of evaluating certain aspects of the Company's capital strength from period to period on a basis that may not be otherwise apparent under GAAP. Management also believes that this non-GAAP financial measure, which complements the capital ratios defined by regulators, is useful to investors who are interested in the Company's equity to assets ratio exclusive of the effect of changes in intangible assets on equity and total assets.

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MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
AND RESULTS OF OPERATIONS

        The following discussion should be read in conjunction with the "Selected Historical Consolidated Financial Information," and our financial statements and related notes thereto included elsewhere in this prospectus. In addition to historical information, this discussion contains forward-looking statements that involve risks, uncertainties and assumptions that could cause actual results to differ materially from management's expectations. Factors that could cause such differences are discussed in the sections entitled "Cautionary Note Regarding Forward-Looking Statements" and "Risk Factors." We assume no obligation to update any of these forward-looking statements.

Overview

        BankUnited, Inc. is a savings and loan holding company with two wholly-owned subsidiaries: BankUnited, which is one of the largest independent depository institutions headquartered in Florida by assets, and BankUnited Investment Services, a Florida insurance agency. As of the close of business on May 21, 2009, BankUnited entered into the Purchase and Assumption Agreement including the Loss Sharing Agreements with the FDIC to acquire substantially all of the assets and assume all of the non-brokered deposits and substantially all other liabilities of the Failed Bank. The Failed Bank was closed by the OTS and placed into receivership with the FDIC on May 21, 2009. Neither the Company nor the Bank had any substantive operations prior to the Acquisition.

        BankUnited has a network of 78 branches in 13 Florida counties as of September 30, 2010. Since the Acquisition, we have focused on providing a full range of commercial and consumer banking services to growing companies and their executives, commercial and middle-market businesses and consumers in Florida's coastal regions. Through BankUnited, we deliver a comprehensive range of traditional depository and lending products, online banking services and cash management tools to our customers. Through its non-bank subsidiary, BankUnited Investment Services, the Company offers wealth management products as well as succession planning, estate planning and financial planning services. The Company recently acquired two businesses to start its leasing platform on a national basis. Through United Capital Business Lending, we offer equipment financing services and through Pinnacle Public Finance, we offer municipal leasing services.

Periods Presented and Factors Affecting Comparability

        Financial information presented throughout this "Management's Discussion and Analysis of Financial Condition and Results of Operations" for the nine months ended September 30, 2010 and the period from May 22, 2009 through December 31, 2009 (which we refer to as the post-Acquisition periods) is that of the Company. Historical financial information for the period from October 1, 2008 through May 21, 2009 and the fiscal years ended September 30, 2008, 2007, 2006 and 2005 (which we refer to as the pre-Acquisition periods) is that of the Failed Bank. Results of operations of the Company for the post-Acquisition periods are not comparable to the results of operations of the Failed Bank for the pre-Acquisition periods. Results of operations for the post-Acquisition periods reflect, among other things, the acquisition method of accounting.

        Under the acquisition method of accounting, all of the assets acquired and liabilities assumed were initially recorded on the consolidated balance sheet of the Company at their estimated fair values as of May 21, 2009. These estimated fair values differed substantially from the carrying amounts of the assets acquired and liabilities assumed as reflected in the financial statements of the Failed Bank immediately prior to the Acquisition. The most significant reasons for the non-comparability of the consolidated financial statements include:

•

The estimated fair value at which the acquired loans were initially recorded by the Company was significantly less than the pre-Acquisition carrying value of those loans on the balance sheet of the Failed Bank. No allowance for loan losses was recorded with respect to acquired loans at the

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Acquisition date. The writedown of loans to fair value in conjunction with the application of acquisition accounting and credit protection provided by the Loss Sharing Agreements resulted in a significantly lower provision for loan losses subsequent to the Acquisition;

•

Acquired investment securities were recorded at their estimated fair values at the Acquisition date, significantly reducing the potential for other-than-temporary impairment charges in periods subsequent to the Acquisition for the acquired securities;



•

An indemnification asset related to the Loss Sharing Agreements with the FDIC was recorded in conjunction with the Acquisition;



•

Interest income, interest expense and the net interest margin subsequent to the Acquisition reflect the impact of accretion of the fair value adjustments made to the carrying amounts of interest earning assets and interest bearing liabilities;



•

Non-interest income for periods subsequent to the Acquisition includes the effects of accretion of discount on the indemnification asset and net gains associated with the resolution of Covered Assets;



•

Certain loans reflected as nonaccrual loans in the financial statements of the Failed Bank are no longer categorized as non-performing assets due to classification of such loans as ACI loans in accordance with ASC Subtopic 310-30,Loan and Debt Securities Acquired with Deteriorated Credit Quality. The balances of non-performing assets were significantly reduced by the adjustments to fair value recorded in conjunction with the Acquisition;



•

Goodwill was recorded in conjunction with the Acquisition;



•

The Company received $2.2 billion in cash from the FDIC upon consummation of the Acquisition; and



•

The Company received a capital injection of $945.0 million at inception.

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        A summary comparison of the pre-Acquisition carrying amounts and estimated fair values of assets acquired and liabilities assumed as of the Acquisition date follows(dollars in thousands):

Primary Factors Used to Evaluate Our Business

        As a financial institution, we manage and evaluate various aspects of both our results of operations and our financial condition. We evaluate the levels and trends of the line items included in our balance sheet and income statement, as well as various financial ratios that are commonly used in our industry. We analyze these ratios and financial trends against our own historical performance, our budgeted performance and the financial condition and performance of comparable financial institutions in our region and nationally.

        Subsequent to the Acquisition, comparison of our financial performance against other financial institutions is impacted by the application of the acquisition method of accounting and the accounting for loans acquired with evidence of deterioration in credit quality, which we refer to as ACI loans, as discussed below.

Results of operations

        The primary line items we use to manage and evaluate our results of operations include net interest income, the provision for loan losses, non-interest income, non-interest expense and net income.

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Net interest income

        Net interest income is the difference between interest earned on interest earning assets and interest incurred on interest bearing liabilities and is the primary driver of core earnings. Net interest income is impacted by the relative mix of interest earning assets and interest bearing liabilities, the ratio of interest earning assets to total assets and of interest bearing liabilities to total funding sources, movements in market interest rates, levels of non-performing assets and pricing pressure from competitors. Due to the revaluation of Covered Assets in conjunction with the application of acquisition accounting and the resultant accretion, generally Covered Assets have higher yields than do assets purchased or originated since May 21, 2009. Net interest income will be impacted in future periods as Covered Assets are repaid or mature and these assets comprise a lower percentage of total interest earning assets. The mix of interest earning assets is influenced by loan demand and by management's continual assessment of the rate of return and relative risk associated with various classes of earning assets.

        The mix of interest bearing liabilities is influenced by management's assessment of the need for lower cost funding sources weighed against relationships with customers and growth requirements and is impacted by competition for deposits in the Bank's market and the availability and pricing of other sources of funds.

        Key measures that we use to evaluate our net interest income are the level and stability of the net interest margin and the interest rate spread. Net interest margin is calculated by dividing net interest income for the period by average interest earning assets. The interest rate spread is the difference between the yield earned on average interest earning assets and the rate paid on average interest bearing liabilities for the period.

        For the post-Acquisition periods, net interest income is also impacted by accretion of fair value adjustments recorded in conjunction with the Acquisition and the accounting for ACI loans. Fair value adjustments of interest earning assets and interest bearing liabilities recorded at Acquisition are accreted to interest income or expense over the lives of the related assets or liabilities. Generally, accretion of fair value adjustments increases interest income and decreases interest expense, and thus has a positive impact on our net interest income, net interest margin and interest rate spread.

        At Acquisition, ACI loans were recorded at fair value, measured based on the present value of expected cash flows. The excess of expected cash flows over the recorded fair value at Acquisition, known as accretable yield, is being recognized as interest income over the lives of the underlying loans. Since the post-Acquisition carrying value of ACI loans is based on the amount expected to be collected, and due to the resultant accretion, these loans are not classified as nonaccrual, although they may be contractually delinquent. Accretion related to ACI loans has a positive impact on our net interest income, net interest margin and interest rate spread. The impact of accretion and ACI loan accounting on net interest income makes it difficult to compare our net interest margin and interest rate spread to those reported by other financial institutions.

        The accretion of fair value adjustments will continue to have a significant impact on our net interest income as long as Covered Assets represent a significant portion of our interest earning assets as opposed to assets originated or purchased after May 21, 2009. At September 30, 2010, Covered Loans represented 91.7% of our loan portfolio (based on book value) and Covered Securities represented 8.8% of our investment portfolio. In total, covered interest earning assets represented 51.5% of our interest earning assets at September 30, 2010.

        Interest expense incurred on our interest bearing liabilities is impacted by the accretion of fair value adjustments on our time deposits and our advances from the FHLB recorded in connection with the Acquisition. However, the impact on interest expense has decreased significantly in 2010 and will continue to decrease in 2011. Accretion of fair value adjustments on time deposits totaled $18.3 million for the nine months ending September 30, 2010 (and is projected to be $21.4 million for 2010) as

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compared to $79.9 million for the period ending December 31, 2009. Accretion of fair value adjustments on FHLB advances totaled $19.0 million for the nine months ended September 30, 2010 (and is projected to be $23.9 million for 2010) as compared to $25.1 million for the period ended December 31, 2009. For 2011, accretion of fair value adjustments on time deposits is projected to be $7.0 million, and accretion of fair value adjustments on FHLB advances is projected to be $19.1 million.

Provision for loan losses

        The provision for loan losses is the amount of expense that, based on our judgment, is required to maintain the allowance for loan losses at an adequate level to absorb probable losses inherent in the loan portfolio at the balance sheet date and that, in management's judgment, is appropriate under U.S. generally accepted accounting principles. The determination of the amount of the allowance is complex and involves a high degree of judgment and subjectivity.

        The risk of loss associated with Covered Loans differs significantly from the risk of loss associated with non-Covered Loans. The Loss Sharing Agreements significantly limit the Company's exposure to credit losses on Covered Loans. Recognition of future losses on Covered Loans is also mitigated by the fair market value of loans established in the application of acquisition accounting. Because the determination of fair value at which the loans acquired from the Failed Bank were initially recorded as of May 21, 2009 encompassed assumptions about expected future cash flows and credit risk, no allowance for loan losses was recorded at the date of acquisition. Fair value adjustments to the carrying amount of acquired loans totaled $6.2 billion.

        Covered Loans may be further broken out into two broad categories: (i) ACI loans and (ii) loans that did not exhibit evidence of deterioration in credit quality at acquisition, or non-ACI loans. Subsequent to the Acquisition, an allowance for loan losses related to the ACI loans is recorded only when estimates of future cash flows related to these loans are revised downward, indicating further deterioration in credit quality. An allowance for loan losses for non-ACI loans may be established if factors considered relevant by management indicate that the credit quality of the non-ACI loans has deteriorated.

        Since the recording of a provision for loan losses on Covered Loans represents an increase in the amount of reimbursement we expect to receive from the FDIC, we also record an increase in the FDIC indemnification asset for the present value of the projected increase in reimbursement, with a corresponding increase in non-interest income, recorded in "Net loss on indemnification asset resulting from net recoveries" as discussed below in the section entitled "—Non-interest income." Therefore, the impact on our results of operations of any provision for loan losses on Covered Loans is significantly mitigated by an increase in non-interest income. For the nine months ended September 30, 2010 and the period ended December 31, 2009, we recorded provisions for loan losses on Covered Loans of $42.5 million and $21.3 million, respectively. For the nine months ended September 30, 2010 and the period ended December 31, 2009, the impact to earnings from these provisions was significantly mitigated by recording non-interest income of $23.0 million and $14.4 million, respectively.

        For the nine months ended September 30, 2010 and the period ended December 31, 2009, we recorded provisions for loan losses of $2.6 million and $1.3 million, respectively, for loans we originated or purchased subsequent to the Acquisition. These loans are not protected by the Loss Sharing Agreements and as such, these provisions are not offset by an increase in non-interest income.

Non-interest income

        For the nine months ended September 30, 2010 and the period ended December 31, 2009, the majority of our non-interest income resulted from the resolution of assets covered by our Loss Sharing Agreements with the FDIC and accretion of discount on the FDIC indemnification asset. Typically, the primary components of non-interest income of financial institutions are service charges and fees and

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gains or losses related to the sale or valuation of investment securities, loans and other assets. Thus, it is difficult to compare the amount and composition of our non-interest income with that of other financial institutions of our size both regionally and nationally.

        The FDIC indemnification asset was initially recorded at its estimated fair value of $3.4 billion, represented by the present value of estimated future cash payments from the FDIC for probable losses on Covered Assets, up to 90 days of past due interest, excluding loans on nonaccrual at Acquisition, and reimbursement of certain expenses. The discount rate of 7.10% used in the initial calculation of fair value was determined using a risk-free yield curve plus a premium reflecting the uncertainty related to the collection, amount and timing of the cash flows and other liquidity concerns. Accretion is a result of discounting and may also increase or decrease from period to period due to changes in expected cash flows from the Covered Loans.

        If projected cash flows from the ACI loans increase, the yield on the loans will increase and the discount rate of accretion on the FDIC indemnification asset will decrease as less cash flow is expected to be recovered from the indemnification asset. For the nine months ended September 30, 2010 and the period ended December 31, 2009, the average rate at which income was accreted on the FDIC indemnification asset was 5.32% and 7.10%, respectively.

        A rollforward of the FDIC indemnification asset from May 21, 2009 to September 30, 2010 follows(dollars in thousands):

        Accretion of the discount on the FDIC indemnification asset results in an increase to the balance of the FDIC indemnification asset with a corresponding increase in non-interest income. We project the amount of accretion will decline in future periods, because our projected cash flows from ACI loans have been increasing, and as a result we expect to collect less cash flow from the indemnification asset as discussed above.

        The balance of the FDIC indemnification asset is reduced as claims for reimbursement are filed with the FDIC. The receipt of payments from the FDIC results in an increase to cash.

        The balance of the FDIC indemnification asset has also been reduced as a result of decreases in estimated cash flows to be received from the FDIC related to the ultimate resolution of Covered Assets. We record an offsetting entry in the income statement line item "Net loss on indemnification asset resulting from net recoveries." This line item includes the significantly mitigating impact related to loan loss provisions on Covered Loans, the impact of lower projected FDIC reimbursement resulting from the favorable resolution of Covered Loans as described below, and the offsetting impact related to gains or losses on the sale of Covered Loans and impairment of OREO. The table below shows the various components of this income statement line item for the nine months ended September 30, 2010 and period ended December 31, 2009.

        Income from resolution of Covered Loans is included in the income statement line item "Income from resolution of Covered Assets, net" and represents the difference in the projected losses from ACI loans and payment received in satisfaction of such loans that were resolved, either by prepayment, sale,

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foreclosure, short sale or, for the non-residential portfolio, charge-offs, as well as losses from permanent modification of ACI loans accounted for in pools during the period. Gains and losses from the resolution or permanent modification of Covered Loans are included in this line item. The amount of income recorded in any period will be impacted by the number and UPB of ACI loans resolved and our ability to accurately project cash flows from ACI loans in future periods. In general, we expect the amount of this income to decrease in future periods as we gain additional history in terms of the performance of the loans we acquired, which we will reflect in the update of our projected cash flows from ACI loans each quarter. Income from the resolution of non-ACI loans is not significant.

        Under the Purchase and Assumption Agreement, we are permitted to sell on an annual basis up to 2.5% of the Covered Loans, based upon the UPB at Acquisition, or approximately $280.0 million, without prior consent of the FDIC. Any losses incurred from such loan sales are covered under the Loss Sharing Agreements. A loss of $47.1 million was recognized during the period ending December 31, 2009 on non-recourse sales of ACI loans with UPB of $275.0 million to third parties. This loss was significantly mitigated by income of approximately $37.6 million, included in the income statement line item "Net loss on indemnification asset resulting from net recoveries." We may continue to exercise our right to sell Covered Loans in future periods.

        The following table summarizes the pre-tax components of the gains and losses associated with the resolution of Covered Assets as described above, plus the provision for loan losses on non-Covered Loans, for the nine months ended September 30, 2010 and period ended December 31, 2009(dollars in thousands):

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        The following table provides further detail of the components of income from resolution of Covered Assets, net: