UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K/A

Amendment No. 1

(Mark one)

For the Fiscal Year Ended December 31, 2012

For the transition period from to

COMMISSION FILE NUMBER 001-14793

FIRST BANCORP.

(EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)

Registrant’s telephone number, including area code:

(787) 729-8200

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to Section 12(g) of the Act:

7.125% Noncumulative Perpetual Monthly Income Preferred Stock, Series A (CUSIP: 318672201);

8.35% Noncumulative Perpetual Monthly Income Preferred Stock, Series B (CUSIP: 318672300);

7.40% Noncumulative Perpetual Monthly Income Preferred Stock, Series C (CUSIP: 318672409);

7.25% Noncumulative Perpetual Monthly Income Preferred Stock, Series D (CUSIP: 318672508; and

7.00% Noncumulative Perpetual Monthly Preferred Stock, Series E (CUSIP: 318672607)

Indicate by check mark if the registrant is a well- known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ¨ No þ

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes ¨ No þ

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes þ No ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Website, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes þ No ¨

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definite proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. ¨

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

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ¨ No þ

The aggregate market value of the voting common equity held by non-affiliates of the registrant as of June 29, 2012 (the last trading day of the registrant’s most recently completed second quarter) was $409,983,908 based on the closing price of $3.96 per share of common stock on the New York Stock Exchange on June 29, 2012. The registrant had no nonvoting common equity outstanding as of June 29, 2012. For the purposes of the foregoing calculation only, registrant has treated as common stock held by affiliates only common stock of the registrant held or represented by its directors and executive officers and voting stock held by the registrant’s employee benefit plans. The registrant’s response to this item is not intended to be an admission that any person is an affiliate of the registrant for any purposes other than this response.

Indicate the number of shares outstanding of each of the registrant’s classes of common stock, as of the latest practicable date: 206,325,465 shares as of March 15, 2013.

EXPLANATORY NOTE

This Amendment No. 1 to the Annual Report on Form 10-K of First BanCorp. (the “Corporation”) for the fiscal year ended December 31, 2012 is being filed for the sole purpose of refiling Exhibit 99.3 because a portion of the exhibit was inadvertently omitted due to a financial printer error.

This Amendment No. 1 makes no other changes to the Annual Report on Form 10-K as filed with the U.S. Securities and Exchange Commission on April 1, 2013.

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Item 15. Exhibits, Financial Statement Schedules

The following consolidated financial statements of First BanCorp., together with the report thereon of First BanCorp.’s independent registered public accounting firm, KPMG LLP, dated April 1, 2013, are included herein beginning on page F-1:

All financial schedules have been omitted because they are not applicable or the required information is shown in the financial statements or notes thereto.

EXHIBIT INDEX

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 the Corporation has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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