SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported): February 22, 2016

Bank of the Ozarks, Inc.

(Exact Name of Registrant as Specified in Charter)

17901 Chenal Parkway

Little Rock, Arkansas 72223

(Address of Principal Executive Offices)

(501) 978-2265

(Registrant’s telephone number, including area code)

N/A

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

As previously disclosed in the proxy statement/prospectus dated February 1, 2016 (the “Merger Proxy”) relating to the proposed merger (the “Merger”) of C1 Financial, Inc. (“C1”) with and into Bank of the Ozarks, Inc. (“Ozarks” or the “Company”), pursuant to the Agreement and Plan of Merger (the “Merger Agreement”), dated as of November 9, 2015, by and among Ozarks, Ozarks’ wholly owned subsidiary, Bank of the Ozarks, C1 and C1’s wholly owned subsidiary, C1 Bank, a purported shareholder class action complaint was filed in the Court of the Sixth Circuit in Pinellas County, Florida (the “Court”) against C1 and the individual members of C1’s board of directors, and Ozarks (the “Action”). The Action generally alleged claims for breach of fiduciary duty by the individual directors of C1 and also alleges that C1 and Ozarks have aided and abetted the C1 board members’ breaches of their fiduciary duties. On January 22, 2016, the plaintiff in the Action filed an amended complaint adding, among other things, allegations of material misstatements and omissions concerning the content of the preliminary Registration Statement on Form S-4 filed by Ozarks on January 5, 2016. The Action requests, among other things, that the Merger be enjoined.

On February 22, 2016, the parties to the Action entered into a memorandum of understanding (the “MOU”) reflecting the terms of an agreement, subject to final approval by the Court and certain other conditions, to settle the Action. Pursuant to the MOU, and without admitting any wrongdoing or that these supplemental disclosures are material or required to be made, defendants agreed to make certain supplemental disclosures requested by plaintiffs in the Action. The MOU further provides that, among other things, (a) after the completion of reasonable confirmatory discovery the parties will negotiate a definitive stipulation of settlement (the “Stipulation”) and will submit the Stipulation to the Court for review and approval; (b) the Stipulation will provide for dismissal of the Action with prejudice; (c) the Stipulation will include a general release of defendants of claims relating to, among other things, the Merger and the Merger Agreement; and (d) the settlement is conditioned on, among other things, consummation of the Merger, class certification and final approval by the Court after notice to C1’s shareholders. Defendants believe that the allegations and claims in the litigation are without merit and, if the settlement does not receive final approval, intend to defend them vigorously. Defendants are entering into the settlement solely to eliminate the burden and expense of further litigation and to put the claims that were or could have been asserted to rest. The settlement will not affect the timing of the Merger or the amount of consideration to be paid in the Merger.

The supplemental disclosures are contained below. This supplemental information should be read in conjunction with the Merger Proxy, which should be read in its entirety. To the extent that information herein differs from or updates information contained in the Merger Proxy, the information contained herein is more current. Defined terms used but not defined herein have the meanings set forth in the Merger Proxy. Paragraph references used herein refer to the Merger Proxy prior to any additions or deletions resulting from the supplemental disclosures.

Under the caption “Background of the Merger”, the following sentence is added at the end of the third full paragraph on page 42:

“The C1 board approved the engagement of Sandler O’Neill after members of C1 management had discussions with, and the Executive Committee of the C1 board considered the qualifications of, other potential financial advisors. The Executive Committee of the C1 board approved the engagement of Sandler O’Neill based on Sandler O’Neill’s reputation and experience with similar engagements and the commitment of a particular principal of Sandler O’Neill (known to be knowledgeable about C1 and the industry) that he would be personally involved in advising the C1 board with respect to considering potential strategic alternatives, including a potential business combination.”

Under the caption “Background of the Merger”, the second sentence of the sixth full paragraph on page 42 is deleted and replaced with the following:

“Prior to September 23, 2015, C1 or Sandler O’Neill had in-person meetings or conference calls with each of the nine companies, during which time C1 and Sandler O’Neill attempted to gauge each company’s interest in pursuing a potential transaction. On September 23, 2015, C1 received two written expressions of interest: one from Ozarks and one from a financial institution we refer to as Company A.”

Under the caption “Background of the Merger”, the following sentence is added at the end of the sixth full paragraph on page 42:

“Sandler O’Neill contacted each of the other seven companies, and each company either confirmed that it was not going to submit an indication of interest or did not respond to Sandler O’Neill’s inquiry.”

Under the caption “Background of the Merger”, the following sentence is added at the end of the second full paragraph on page 43:

“Sandler O’Neill contacted Company A shortly after Company A submitted its proposal to see whether it would be willing to improve its proposal. Company A did not indicate that it was willing to meaningfully improve its proposal.”

Under the caption “Background of the Merger”, the sixth sentence of the fourth paragraph on page 43 is deleted and replaced with the following:

“As part of this the C1 board also discussed certain management projections, which projections were previously approved by the C1 board and provided to Ozarks, Company A and other interested parties that had signed confidentiality agreements, and noted that, although there were certain theoretical upside scenarios, such upside scenarios were limited, and, on the other hand, there were meaningful potential downside scenarios, including with respect to certain Brazilian loans that had been made to unaffiliated parties by C1 Bank (and are referred to as the Brazilian loans) and the possible slowing of loan growth. Mr. Burgess also noted that at that time C1 was performing in-line with or below such management projections.”

Under the caption “Background of the Merger”, the following sentence is added at the end of the eighth sentence of the fourth paragraph on page 43 (running from page 43 to 44):

“The C1 board also discussed that the average daily trading volume of Ozarks common stock would allow C1’s shareholders the opportunity for liquidity.”

Under the caption “Background of the Merger”, the following sentence is added at the end of the first sentence of the first full paragraph on page 44:

“The board also considered the low likelihood of Company A materially improving its proposal such that it would be superior to Ozarks’ proposal and the risk that continued negotiations with Company A could disrupt or delay C1’s potential negotiations with Ozarks and decrease the likelihood of a transaction with Ozarks, particularly in light of Ozarks’ statement that its willingness to proceed with its proposal was subject to being granted a period of exclusivity.”

Under the caption “Background of the Merger”, the second sentence of the second full paragraph on page 44 is deleted and replaced with the following:

“During the discussions, Messrs. Burgess and Glaser pressed Mr. Dennis James, Executive Vice President and Director of Mergers and Acquisitions of Ozarks, for Ozarks to increase its proposed purchase price. Mr. James, however, advised Messrs. Burgess and Glaser that Ozarks’ best and final price was the $25.00 per share price, subject to the collar and net worth adjustment, as set forth in Ozarks’ September 23, 2015 expression of interest.”

Under the caption “Background of the Merger”, the following sentence is added at the end of the fourth sentence of the third full paragraph on page 44:

“In addition, the C1 board discussed the tax implications of the proposed transaction with Ozarks and C1’s shareholders’ ability to resell Ozarks common stock received in the proposed transaction following the closing of the proposed transaction.”

Under the caption “Background of the Merger”, the following sentence is added at the end of the sixth sentence of the third full paragraph on page 44:

“The board agreed to authorize C1 to agree to the 20 day exclusivity period after considering the transaction process generally and the proposals in particular. The board considered that over 35 financial institutions had been contacted and only Ozarks and Company A had made preliminary proposals. The C1 board also considered Ozarks’ proposal compared to Company A’s proposal, including that Ozarks’ proposal offered an

attractive premium, whereas Company A’s proposal was at a discount to the trading price of C1 shares and the board’s view that Company A was unlikely to materially improve its proposal and that even if Company A were to materially improve its proposal that it would be unlikely that the proposal would be superior to Ozarks’ proposal.”

Under the caption “Background of the Merger”, the fourth full paragraph on page 44 is deleted and replaced with the following:

“During the weeks of September 28, October 5 and October 12 and thereafter, Ozarks, together with its legal advisors, intensified its business, legal and financial due diligence of C1. During this time and also during the week of September 21, Mr. Burgess had high level discussions with representatives of Ozarks with respect to Mr. Burgess’ potential role at Ozarks following completion of the proposed transaction. At various times during these discussions representatives of Ozarks stated that Ozarks would not be willing to proceed with the proposed transaction if Mr. Burgess were not retained. Mr. Burgess regularly updated C1 independent directors regarding these discussions.”

Under the caption “Background of the Merger”, the following sentence is added at the end of the first full paragraph on page 45:

“The independent directors also discussed the potential impact of a change of control or bonus payment to Mr. Burgess on C1’s net book value for purposes of the purchase price adjustment included in Ozarks’ September 23 proposal.”

Under the caption “Background of the Merger”, the sixth paragraph on page 45 (running from page 45 to 46) is deleted and replaced with the following:

“On October 16, 2015, the C1 board held a special meeting to discuss the status of discussions with Ozarks. At the invitation of the C1 board, representatives from Davis Polk and Shutts were present. Davis Polk reviewed with the C1 board the directors’ fiduciary duties and other legal matters relating to the consideration of a possible strategic transaction. The C1 board and its advisors discussed that Ozarks was not willing to proceed with the proposed transaction unless C1 disposed of the Brazilian loans. The C1 board and its advisors considered and discussed that if it were to conduct a pre-signing fulsome marketing process for the Brazilian loans, which would be reasonably likely to maximize the value of the Brazilian loans, this would considerably delay execution of the proposed transaction with Ozarks and could jeopardize the proposed transaction with Ozarks altogether. The board and its advisors discussed that Mr. Lima was willing, in order to facilitate the proposed transaction, to agree or to cause one of his affiliates to agree to purchase the Brazilian loans on a standby basis as described above. The C1 board and its advisors discussed that, as an alternative to conducting a pre-signing marketing process, C1 could agree to sell the loans to Mr. Lima on a standby basis and between signing and closing, a committee of independent directors could engage an independent broker and seek to find a buyer for the Brazilian loans who might be willing to pay more for them than the amount agreed to in principle by Mr. Lima. The C1 board and its advisors also discussed the fact that Ozarks had agreed that if such loans were sold for an amount in excess of the standby purchase price, the aggregate purchase price for the proposed transaction would be increased on an after-tax, dollar-for dollar basis. During the meeting Mr. Burgess also noted that he received an inquiry from a broker the previous week regarding a sale of C1. The C1 board agreed that based on the identity of the broker and the nature of the inquiry that the inquiry was not reasonably likely to lead to a superior transaction compared to the proposed transaction with Ozarks. While the C1 board made no decision with respect to the potential sale of C1 to Ozarks, it authorized Mr. Burgess to execute an extension of the exclusivity period until November 2, 2015 and authorized continuing discussions and negotiations with Ozarks. The C1 independent directors then met in executive session and after discussion approved the actions taken by the C1 board.”

Under the caption “Background of the Merger”, the following sentence is added at the end of the fifth full paragraph on page 46:

“Sandler O’Neill noted that it had provided advice to companies which Ozarks had acquired or agreed to acquire, and that it had acted as financial advisor to C&S.”

Under the caption “Background of the Merger”, the following paragraph is added at the end of the fourth full paragraph on page 47:

“During the meeting Mr. Burgess also noted that he received an inquiry from an analyst suggesting that he reach out to the analyst if C1 were interested in talking about growth or an exit. The C1 board discussed the inquiry and agreed that based on the identity of the analyst and the nature of the inquiry that the inquiry was not reasonably likely to lead to a superior transaction compared to the proposed transaction with Ozarks.”

Under the caption “Background of the Merger”, the following sentence is added at the end of the fifth sentence of the fifth paragraph on page 47:

“The C1 board also discussed Mr. Burgess’ entry into a change of control agreement with C1 and his proposed entry into a retention and non-compete agreement with Ozarks Bank.”

Under the caption “Opinion of C1’s Financial Advisor”, the last sentence of the first full paragraph on page 57 is deleted and replaced with the following:

“The table below sets forth the data for C1 and the C1 Peer Group.”

Under the caption “Opinion of C1’s Financial Advisor”, the table after the first full paragraph on page 57 is deleted and replaced with the following:

Under the caption “Opinion of C1’s Financial Advisor”, the last sentence of the first full paragraph on page 58 is deleted and replaced with the following:

“The table below sets forth the data for Ozarks and the Ozarks Peer Group.”

Under the caption “Opinion of C1’s Financial Advisor”, the table after the first full paragraph on page 58 is deleted and replaced with the following:

Under the caption “Opinion of C1’s Financial Advisor”, the second sentence of the second full paragraph on page 58 is deleted and replaced with the following:

“Sandler O’Neill relied on publicly available analyst earnings per share estimates for the years ending December 31, 2015 through December 31, 2017 and an estimated long term earnings growth rate for the years thereafter of 15% because the senior management of C1 indicated that the C1 2015 Management Projections (as described in the section titled “The Merger—Certain Financial Projections”) were outdated and that the publicly available analyst earnings per share estimates for the years ending December 31, 2015 through December 31, 2017 and a 15% long term earnings growth rate for the period thereafter represented reasonable projections for future earnings performance of C1 given, among other things, C1’s recent operating trends. This net present value analysis resulted in financial projections for C1 for each of the years ending December 31, 2015 through December 31, 2019, which are referred to as the “Extrapolated Analyst Projections for C1”.”

Under the caption “Opinion of C1’s Financial Advisor”, the third sentence of the third full paragraph on page 59 (running from page 59 to 60) is deleted and replaced with the following:

“Since C1 common stock had an average daily trading volume of less than 23,000 shares per day over the twelve month period ending November 6, 2015, and a market cap of approximately $333.3 million as of November 6, 2015, Sandler O’Neill determined, consistent with the Duff & Phelps valuation handbook, that it was prudent to use a Duff & Phelps size premium in absence of a beta since C1 common stock was relatively illiquid.”

Under the caption “Opinion of C1’s Financial Advisor” the following sentence is added at the end of the second full paragraph on page 61:

“Because this formulation uses a two-year beta it does use a size premium.”

Under the caption “Opinion of C1’s Financial Advisor”, the second sentence of the first full paragraph on page 62 is deleted and replaced with the following:

“Sandler O’Neill also reviewed the following seller information: tangible common equity to tangible assets, last twelve months’ return on average assets and non-performing assets to total assets. Sandler O’Neill then compared the indicated metrics for the merger to the high, mean, median and low metrics for the Regional Precedent Transactions group.”

Under the caption “Opinion of C1’s Financial Advisor”, the table, and its footnotes, after the first full paragraph on page 62 is deleted and replaced with the following:

Under the caption “Opinion of C1’s Financial Advisor”, the second sentence of the first full paragraph on page 63 is deleted and replaced with the following:

“Sandler O’Neill also reviewed the following seller information: tangible common equity to tangible assets, last twelve months’ return on average assets and non-performing assets to total assets. Sandler O’Neill then compared the indicated metrics for the merger to the high, mean, median and low metrics for the Nationwide Precedent Transactions group.”

Under the caption “Opinion of C1’s Financial Advisor”, the table, and its footnotes, after the first full paragraph on page 63 is deleted and replaced with the following:

Under the caption “Certain Financial Projections”, the two tables after the first sentence on page 66 are deleted and replaced with the following:

Under the caption “Certain Financial Projections”, the following paragraphs and table are added at the end of the third table on page 66:

“Efficiency ratio”, which is defined as total noninterest expense divided by the sum of taxable-equivalent net interest income and noninterest income, is not a measure of financial performance recognized by GAAP. Noninterest income is adjusted for nonrecurring gains and losses on sales of securities.

C1 believes that this ratio is important to investors looking for a measure of efficiency in C1’s productivity, measured by the amount of expense required to generate each dollar of revenue; however, C1 acknowledges that non-GAAP financial measures have a number of limitations. As such, you should not view these disclosures as a substitute for results determined in accordance with GAAP, and they are not necessarily comparable to non-GAAP financial measures that other companies use. The following reconciliation table provides a more detailed analysis of efficiency ratio: