Filed by United Community Banks, Inc.

Pursuant to Rule 425 under the Securities Act of 1933, as amended

and deemed filed pursuant to Rule 14a-12

under the Securities Exchange Act of 1934, as amended

Subject Company: First Miami Bancorp, Inc.

Commission File No.: 001-35095

Date: March 23, 2023

Set forth below is an internal newsletter to employees of First Miami Bancorp, Inc. regarding the proposed merger of First Miami Bancorp, Inc., with and into United Community Banks, Inc.

Merger News:

Key transaction milestone dates*:

• Q3: Legal close

• October 23: Conversion

*subject to regulatory approval

A special website has been set up on ucbi.com for our FNBSM partners and their clients that includes FAQs, resources, press releases, and more!

United News:

Last week, United hosted the annual Senior Leadership Conference in Greenville, SC. Two-hundred leaders from across the footprint met to hear from executives and guest speakers, learn more about our company, and meet teammates.

During the conference, CEO Lynn Harton and CMO Abraham Cox revealed United’s new logo. On Monday, March 20, it was shared with all United employees. A press release is scheduled for distribution across the footprint on Tuesday, March 28 to inform customers about the logo refresh. **Until then, please do not share the new logo or reveal it in any way to your customers.**

If you have any questions, please email LogoRefresh@ucbi.com.

Human Resources:

Base compensation will remain the same for FNBSM employees who will continue in their current position. United HR and FNBSM leaders are evaluating specifics involving job changes, bonuses, incentives, and commission plans. Any changes will be communicated directly to impacted employees soon after legal close in Q3. There will be no change to the performance review/ merit planning process, which is generally effective April 1.

If you have any questions regarding your compensation, we welcome you to use the unique HR inbox set up for FNBSM employees: UnitedTogether_Questions@ucbi.com

Upcoming topics from United’s HR Department:

• 401K retirement and deferred compensation

• Benefits overview

• Payroll

IMPORTANT INFORMATION FOR SHAREHOLDERS AND INVESTORS

In connection with the proposed merger between United Community Banks, Inc. (“United”) and First Miami Bancorp, Inc. (“First Miami”), United intends to file with the SEC a registration statement on Form S-4 that will include a proxy statement of First Miami to be sent to First Miami’s shareholders seeking their approval of the merger agreement. The registration statement also will contain the prospectus of United to register the shares of United common stock to be issued in connection with the Merger. INVESTORS AND SHAREHOLDERS OF FIRST MIAMI ARE ENCOURAGED TO READ THE REGISTRATION STATEMENT, INCLUDING THE PROXY STATEMENT/PROSPECTUS THAT WILL BE A PART OF THE REGISTRATION STATEMENT WHEN IT BECOMES AVAILABLE AND ANY OTHER RELEVANT DOCUMENTS FILED BY UNITED OR FIRST MIAMI WITH THE SEC, INCLUDING ANY AMENDMENTS OR SUPPLEMENTS TO THE REGISTRATION STATEMENT AND THOSE OTHER DOCUMENTS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT UNITED, FIRST MIAMI AND THE MERGER.

The registration statement and other documents filed with the SEC may be obtained for free at the SEC’s website (www.sec.gov). You will also be able to obtain these documents, free of charge, from United at the “Investor Relations” section of United’s website at www.ucbi.com. Copies of the definitive proxy statement/prospectus will also be made available, free of charge, by contacting United Community Banks, Inc., P.O. Box 398, Blairsville, GA 30514, Attn: Jefferson Harralson, Telephone: (864) 240-6208, or First Miami Bancorp, Inc., 5750 Sunset Drive, South Miami, FL 33143, Attn: Pablo Rodriguez, Telephone: (305) 662-5473.

PARTICIPANTS IN THE TRANSACTION

United and First Miami, and certain of their respective directors and executive officers, under the rules of the SEC may be deemed to be participants in the solicitation of proxies from First Miami’s shareholders in favor of the approval of the merger agreement. Information about the directors and officers of United and their ownership of United common stock can be found in United’s definitive proxy statement in connection with its 2022 annual meeting of shareholders, as filed with the SEC on March 25, 2022, and other documents subsequently filed by United with the SEC. Additional information regarding the interests of these participants will also be included in the proxy statement/prospectus pertaining to the transaction if and when it becomes available. Free copies of this document may be obtained as described above.