# EDGAR Filing Document

**Accession Number:** 0001709442
**File Stem:** 0001709442-25-000085
**Filing Date:** 2025-12
**Character Count:** 50622
**Document Hash:** a1a5bc5bb512c644c540239ad92ab35d
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001709442-25-000085.hdr.sgml**: 20251204

**ACCESSION NUMBER**: 0001709442-25-000085

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20251203

**ITEM INFORMATION**: Entry into a Material Definitive Agreement

**ITEM INFORMATION**: Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20251204

**DATE AS OF CHANGE**: 20251204

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** FIRSTSUN CAPITAL BANCORP
- **CENTRAL INDEX KEY:** 0001709442
- **STANDARD INDUSTRIAL CLASSIFICATION:** NATIONAL COMMERCIAL BANKS [6021]
- **ORGANIZATION NAME:** 02 Finance
- **EIN:** 814552413
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-42175
- **FILM NUMBER:** 251548336

**BUSINESS ADDRESS:**
- **STREET 1:** 1400 16TH STREET
- **CITY:** DENVER
- **STATE:** CO
- **ZIP:** 80202
- **BUSINESS PHONE:** 785-827-5565

**MAIL ADDRESS:**
- **STREET 1:** 1400 16TH STREET
- **CITY:** DENVER
- **STATE:** CO
- **ZIP:** 80202

?xml version='1.0' encoding='ASCII'? fcb-20251203

**UNITED STATES**

**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): December 3, 2025**

**FIRSTSUN CAPITAL BANCORP**

**(Exact name of registrant as specified in its charter)**

---

| | | |
|:---|:---|:---|
| **Delaware** | **001-42175** | **81-4552413** |
| **(State or other jurisdiction of** <br>**incorporation or organization)** | **(Commission File Number)** | **(I.R.S. Employer Identification Number)** |

---

**1400 16th Street, Suite 250**

**Denver, Colorado 80202**

**(Address of principal executive offices and zip code)**

**(303) 831-6704**

**(Registrant's telephone number, including area code)**

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:

☒ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

---

| | | |
|:---|:---|:---|
| Securities registered pursuant to Section 12(b) of the Act: | Securities registered pursuant to Section 12(b) of the Act: | Securities registered pursuant to Section 12(b) of the Act: |
| Title of each class | Trading Symbol(s) | Name of each exchange<br> on which registered |
| **Common Stock, $.0001 Par Value** | **FSUN** | **Nasdaq Global Select Market** |

---

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17CFR § 230.405) or 12b-2 of the Exchange Act of 1934 (17 CFR § 240.12b-2).

Emerging growth company ☒&nbsp;&nbsp;&nbsp;&nbsp;

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

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**Item 1.01&nbsp;&nbsp;&nbsp;&nbsp;Entry into a Material Definitive Agreement.**

*Entry into Board Representative Letter Agreement*

On December 3, 2025, FirstSun Capital Bancorp (the "<u>Company</u>") entered into a Board Representative Letter Agreement with Castle Creek Capital Partners IX, LP ("<u>Castle Creek</u>") that provides, beginning with the earlier of (i) the closing of the Company's proposed merger with First Foundation Inc. (the "<u>Proposed Merger Closing</u>") and (ii) the 2026 Annual Meeting of the Stockholders of the Company (the "<u>2026 Annual Meeting</u>") the Company will use its best efforts to cause an individual designated for nomination by Castle Creek to be elected or appointed to the board of directors of the Company and will recommend to its stockholders the election of such individual designated at the applicable stockholders' meetings of the Company. In addition, as of the date of the Board Representative Letter Agreement, to the extent Castle Creek does not have a board representative currently serving on the board of directors, Castle Creek may appoint an individual as a nonvoting observer to the board of directors. Such nomination and observer rights continue for so long as Castle Creek owns at least 40% of the total shares held by Castle Creek as of the date of the Board Representative Letter Agreement. The Board Representative Letter Agreement entered into with Castle Creek is substantially similar to the form of Board Representation Letter Agreements entered into with other stockholders of the Company as described in the Company's Current Report on Form 8-K filed with the Securities Exchange Commission on February 25, 2025.

The foregoing description of the Board Representative Letter Agreement is not complete and is subject to and qualified in its entirety by reference to the full text of such agreement, a copy of which is included as <u>[Exhibit 4.1](exhibit41-boardrepresentat.htm)</u> to this Current Report on Form 8-K.

**Item 5.02 &nbsp;&nbsp;&nbsp;&nbsp;Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.**

On December 3, 2025, Isabella Cunningham announced her intention to resign as a director of the Company with such resignation being effective as of the earlier of (i) the Proposed Merger Closing and (ii) the 2026 Annual Meeting.

Ms. Cunningham has served as a valuable board member of the Company since 2022. In her letter of resignation, Ms. Cunningham expressed her pleasure in serving on the Board of the Company and wished continued success to the Company after her resignation. The Company similarly appreciates her contributions during her tenure. The Company thanks Ms. Cunningham for her service to the Company and wishes her the best in her endeavors following her resignation from the board.

The Company does not anticipate reducing the size of the board upon Ms. Cunningham's resignation but intends to keep the size of the Board the same in order to accommodate the board nominee of Castle Creek at the earlier of the Proposed Merger Closing and the 2026 Annual Meeting.

**Item 8.01 &nbsp;&nbsp;&nbsp;&nbsp;Other Events.**

On December 4, 2025, the Company and Castle Creek issued a joint press release announcing Castle Creek's investment in the Company and related board representation arrangement. A copy of the press release is furnished as <u>[Exhibit 99.1](exhibit991-castlecreekcapi.htm)</u> to this Current Report on Form 8-K.

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**Item 9.01 &nbsp;&nbsp;&nbsp;&nbsp;Financial Statements and Exhibits.**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d) The following exhibit index lists the exhibits that are either filed or furnished with this Current Report on Form 8-K:

**EXHIBIT INDEX**

---

| | |
|:---|:---|
| **Exhibit Number** | **Description** |
| 4.1 | <u>[Form of Board Representative Letter Agreement](exhibit41-boardrepresentat.htm)</u> |
| 99.1 | <u>[Joint Press Release, dated December 4, 2025](exhibit991-castlecreekcapi.htm)</u> |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document). |

---

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**SIGNATURE**

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

---

| | | |
|:---|:---|:---|
| | **FIRSTSUN CAPITAL BANCORP** | **FIRSTSUN CAPITAL BANCORP** |
| Date: February 25, 2025 | By: | /s/ Neal E. Arnold |
|  | Name: | Neal E. Arnold |
|  | Title: | Chief Executive Officer |

---

## Exhibit 4.1

**Exhibit 4.1**

**BOARD REPRESENTATIVE LETTER AGREEMENT**

FirstSun Capital Bancorp<br>1400 16<sup>th</sup> Street, Suite 250<br>Denver, Colorado 80202

December 3, 2025

Castle Creek Capital Partners IX, LP

Attn: Spencer Cohn

Dear Sir or Madam:

For good and valuable consideration acknowledged to have been received, FirstSun Capital Bancorp (the "***Company***") and Castle Creek Capital Partners IX, LP (the "***Investor***"), agree as follows:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**1.**Beginning upon the earlier of (i) the closing of the Company's merger with First Foundation Inc. and (ii) the 2026 Annual Meeting of the Stockholders of the Company, the Company will use its best efforts to cause an individual designated for nomination by Investor (the "***Board Representative***") to be elected or appointed to the board of directors of the Company (the "***Board***"), subject to satisfaction of all legal and regulatory requirements regarding service and election or appointment as a director of the Company; provided that Investor's right to designate for nomination the Board Representative will continue only so long as Investor, together with its Affiliates, in the aggregate owns 40% of the total shares of the Company that the Investor owns as of the date of this letter (the "***Minimum Ownership Interest***"). As used in this letter agreement, "***Affiliates***" means, with respect to any person, any other person that, directly or indirectly through one or more intermediaries, controls, is controlled by, or is under common control with such person, as such terms are used in and construed in Rule 405 under the Securities Act of 1933. With respect to Investor, any investment fund or managed account that is managed on a discretionary basis by the same investment manager as Investor will be deemed to be an Affiliate of Investor.

So long as Investor, together with its Affiliates, has a Minimum Ownership Interest, the Company will recommend to its stockholders the election of the Board Representative to the Board at all of the Company's meetings of stockholders, subject to satisfaction of all legal requirements regarding service and election or appointment as a director of the Company. If Investor no longer has a Minimum Ownership Interest, Investor (i) shall promptly notify the Company of such fact, (ii) will have no further rights under Section 1(a) through (e), and (iii) at the written request of the Board, shall use commercially reasonable efforts to cause the Board Representative to resign from the Board as promptly as possible thereafter

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a)Subject to applicable law and this Section 1, the Board Representative shall be one of the Company's nominees to serve on the Board. The Company shall use its reasonable best efforts to have the Board Representative elected as a director of the Company by

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the stockholders of the Company, and the Company shall solicit proxies for the Board Representative to the same extent as it does for any of its other Company nominees to the Board.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b)Subject to this Section 1, upon the death, resignation, retirement, disqualification, or removal from office as a member of the Board of the Board Representative, Investor shall have the right to designate the replacement for the Board Representative, provided such replacement satisfies all legal and regulatory requirements regarding service and election or appointment as a director of the Board. The Board shall use its reasonable best efforts to take all action required to fill the vacancy resulting therefrom with such person (including such person, subject to applicable Law, being one of the Company's nominees to serve on the Board), using reasonable best efforts to have such person elected as director of the Company by the stockholders of the Company and the Company soliciting proxies for such person to the same extent as it does for any of its other nominees to the Board.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c)The Company hereby agrees that, from and after the date of this letter agreement, for so long as Investor and its Affiliates in the aggregate have a Minimum Ownership Interest, and do not have a Board Representative currently serving on the Board (or have a Board Representative whose appointment is subject to receipt of regulatory approvals), the Company shall invite a person designated by Investor (the "***Observer***") to attend meetings of the Board, in a nonvoting, nonparticipating observer capacity. The Observer shall not have any right to vote on any matter presented to the Board or any committee thereof. The Company shall give the Observer written notice of each meeting of the Board at the same time and in the same manner as the members of the Board, shall provide the Observer with all written materials and other information given to members of the Board at the same time such materials and information are given to such members (provided, however, that the Observer shall not be provided any Confidential Supervisory Information) and shall permit the Observer to attend as an observer at all meetings thereof. As used herein, "Confidential Supervisory Information" shall mean confidential supervisory information as defined in 12 C.F.R. § 261.2(c), non-public OCC information as defined in 12 C.F.R. § 4.32(b), and as identified in 12 C.F.R. § 309.5(g)(8). In the event the Company proposes to take any action by written consent in lieu of a meeting, the Company shall give written notice thereof to the Observer prior to the effective date of such consent describing the nature and substance of such action and including the proposed text of such written consents. Notwithstanding anything to the contrary contained in this Section 1(c): (i) the Observer may be excluded from executive sessions comprised solely of independent directors if, in the written advice of counsel, such exclusion is necessary in order for the Company to comply with applicable law or stock exchange listing standards (it being understood that it is not expected that the Observer would be excluded from routine executive sessions), and (ii) the Company and the Board shall have the right to withhold any information and to exclude the Observer from any meeting or portion thereof if doing so is, in the written advice of counsel, (A) necessary to protect the attorney-client privilege between such party and counsel, or (B) necessary to avoid a violation of any applicable law or any fiduciary requirements under applicable law, provided that the Company shall use commercially reasonable efforts to provide such information to the Observer in a manner that does not compromise or violate (as applicable) such attorney-client privilege, fiduciary requirements or applicable law. If Investor no longer has a Minimum Ownership Interest, Investor will have no further rights under this Section 1(c).

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;2

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d)The Board Representative shall be entitled to compensation and indemnification and insurance coverage in connection with his or her role as a director to the same extent as other directors on the Board and shall be entitled to prompt reimbursement for reasonable and documented out-of-pocket expenses incurred in attending in meetings of the Board, or any committee thereof in accordance with the policies of the Company. The Company shall notify the Board Representative of all regular meetings and special meetings of the Board and of all regular and special meetings of any committee of the Board. The Company shall provide the Board Representative with copies of all notices, minutes, consents, and other material that it provides to all members of the Board, at the same time such materials are provided to the other respective members.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e)The Company acknowledges that the Board Representative may have certain rights to indemnification, advancement of expenses, and/or insurance provided by Investor and/or its respective Affiliates (collectively, the "***Investor Indemnitors***"). The Company hereby agrees that, with respect to a claim by a Board Representative for indemnification arising out his or her service as a director of the Company, (1) it is the indemnitor of first resort (*i.e.*, its obligations to the Board Representative with respect to indemnification, advancement of expenses, and/or insurance (which obligations shall be the same as, but in no event greater than, any such obligations to members of the Board) are primary and any obligation of the Investor Indemnitors to advance expenses or to provide indemnification for the same expenses or liabilities incurred by the Board Representative are secondary), and (2) the Investor Indemnitors shall have a right of contribution and/or be subrogated to the extent of such advancement or payment to all of the rights of recovery of the Board Representative against the Company.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f)In addition to the foregoing, the Company will reimburse Investor and its Affiliates for all reasonable fees and expenses arising out of or related to the Board Representative's or the Observer's travel to in person meetings of the Board, to the same extent as other directors on the Board.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g)Notwithstanding anything to the contrary contained in this Section 1, the Board may exclude the Board Representative and/or the Observer from portions of meetings of the Board to the extent that the Board will be discussing (i) any matters directly related to Investor or (ii) any exam or other confidential correspondence with the Federal Reserve, the FDIC, or the OCC, in each case to the extent required by applicable Law as reasonably determined by the Company's legal counsel.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(h)Investor covenants and agrees to hold any information obtained from its Board Representative or Observer in confidence, and to cause its Observer to agree to hold in confidence and to act in a fiduciary manner with respect to all information provided to such Observer, in each case except to the extent that such information (i) was previously known by or in the possession of such party on a nonconfidential basis, (ii) is or becomes in the public domain through no fault of such party, (iii) is later lawfully acquired from other sources by the party to which it was furnished, or (iv) is independently developed by such party without the use of such information. Each of the parties to this letter agreement hereby acknowledges that they are aware, and will ensure that their representatives and affiliates are aware, that the United States

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securities laws prohibit any person who has material non-public information about a company from purchasing or selling securities of such company, or from communicating such information to any other person under circumstances in which it is reasonably foreseeable that such person is likely to purchase or sell such securities.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**2.<u>Confidentiality</u>**. Each party to this letter agreement will hold, and will use commercially reasonable efforts to cause its respective subsidiaries and their directors, officers, employees, agents, consultants and advisors to hold, in strict confidence, unless disclosure to any court, administrative agency or commission or other governmental or regulatory authority or instrumentality or self-regulatory organization (each, a "***Governmental Entity***") is reasonably necessary or appropriate in connection with any necessary regulatory approval, or request for information or similar process, or unless compelled to disclose by judicial or administrative process or, based on the advice of its counsel, by another requirement of law or the applicable requirements of any Governmental Entity (in which case, the party permitted to disclose such information shall, to the extent legally permissible and reasonably practicable, provide the other party with prior written notice of such permitted disclosure so that such other party may seek confidential treatment of such information from the applicable Governmental Entity), all nonpublic records, books, contracts, instruments, computer data and other data and information (collectively, "***Information***") concerning the other party hereto furnished to it by such other party or its representatives pursuant to this letter agreement (except to the extent that such information can be shown to have been (a) previously known by such party on a nonconfidential basis, (b) in the public domain through no fault of such party, (c) later lawfully acquired from other sources by the party to which it was furnished, or (d) independently developed or conceived by such party without use of such Information), and neither party hereto shall release or disclose such Information to any other person, except its Affiliates, partners, auditors, attorneys, financial advisors, other consultants and advisors with the express understanding that such parties will maintain the confidentiality of the Information and, to the extent permitted above, to Governmental Entities; provided, however, that (i) the Investor is permitted to disclose Information to auditors and bank and securities regulatory authorities without prior written notice to the Company in connection with any audit or examination that does not explicitly reference the Company or this letter agreement and (ii) the Investor may identify the Company and the number and value of the Investor's security holdings in the Company in accordance with applicable investment reporting and disclosure regulations or internal policies without prior notice to or consent from the Company.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**3.<u>Miscellaneous</u>**.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(a)<u>Notices</u>. Any and all notices or other communications or deliveries required or permitted to be provided hereunder shall be in writing and shall be deemed given and effective on the earliest of (a) the date of transmission, if such notice or communication is delivered via facsimile or e-mail (provided the sender receives a machine-generated confirmation of successful facsimile transmission or e-mail notification or confirmation of receipt of an e-mail transmission) at the facsimile number or e-mail address specified in this Section 3(a) prior to 5:00 p.m., New York City time, on a Business Day, (b) the next Business Day after the date of transmission, if such notice or communication is delivered via facsimile at the facsimile number

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specified in this Section 3(a) on a day that is not a Business Day or later than 5:00 p.m., New York City time, on any business day, (c) the business day following the date of mailing, if sent by U.S. nationally recognized overnight courier service with next day delivery specified, or (d) upon actual receipt by the party to whom such notice is required to be given. The address for such notices and communications shall be as follows:

If to the Company:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

FirstSun Capital Bancorp

1400 16th Street, Suite 250

Denver, Colorado 80202

Attention: Mollie H. Carter

Email: Mollie.Carter@sunflowerbank.com

With a copy to:&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;Nelson Mullins Riley & Scarborough LLP

Atlantic Station

201 17th Street NW, Suite 1700

Atlanta, Georgia 30363

Attention: &nbsp;&nbsp;&nbsp;&nbsp;J. Brennan Ryan

Telephone: &nbsp;&nbsp;&nbsp;&nbsp;(404) 322-6444

Email: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;brennan.ryan@nelsonmullins.com

If to the Investor:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;To the address on record with the Company

or such other address as may be designated in writing hereafter, in the same manner, by such person.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(b)<u>Successors and Assigns</u>. The provisions of this letter agreement may not be assigned by the Investor without the prior written consent of the Company, which consent may be withheld by the Company in its sole discretion, and any purported assignment shall be null and void in the absence of such consent; provided, however that the Investor may assign its rights hereunder in whole or in part to one or more of its Affiliates without the Company's consent. Subject to the foregoing restriction on assignment, this letter agreement will be binding upon, and will inure to the benefit of and be enforceable by, the parties hereto and their respective successors and permitted assigns. Nothing in this letter agreement, express or implied, is intended to confer upon any party other than the parties hereto or their respective successors and assigns any rights, remedies, obligations, or liabilities under or by reason of this letter agreement, except as expressly provided in this letter agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(c)<u>Governing Law</u>. This letter agreement will be governed by and construed in accordance with the Laws of the State of Delaware applicable to contracts made and to be performed entirely within such state. Each party agrees that all proceedings concerning the interpretations, enforcement, and defense of this letter agreement (whether brought against a party hereto or its respective affiliates, employees, or agents) may be commenced on an exclusive basis in the Delaware courts. Each party hereto hereby irrevocably submits to the non-exclusive jurisdiction of the Delaware courts for the adjudication of any dispute hereunder or in connection herewith, and hereby irrevocably waives, and agrees not to assert in any proceeding,

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any claim that it is not personally subject to the jurisdiction of any such Delaware court, or that such proceeding has been commenced in an improper or inconvenient forum. Each party hereto hereby irrevocably waives personal service of process and consents to process being served in any such proceeding by mailing a copy thereof via registered or certified mail or overnight delivery (with evidence of delivery) to such party at the address in effect for notices to it under this letter agreement and agrees that such service shall constitute good and sufficient service of process and notice thereof. Nothing contained herein shall be deemed to limit in any way any right to serve process in any manner permitted by Law. **EACH PARTY HERETO HEREBY IRREVOCABLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS LETTER AGREEMENT OR THE TRANSACTIONS.**

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(d)<u>Severability</u>. If any provision of this letter agreement is held to be invalid or unenforceable in any respect, the validity and enforceability of the remaining terms and provisions of this letter agreement shall not in any way be affected or impaired thereby and the parties will attempt to agree upon a valid and enforceable provision that is a reasonable substitute therefor, and upon so agreeing, shall incorporate such substitute provision in this letter agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(e)<u>Amendments; Waivers, No Additional Consideration</u>. No amendment or waiver of any provision of this letter agreement will be effective with respect to any party unless made in writing and signed by an officer or a duly authorized representative of such party. No waiver of any default with respect to any provision, condition or requirement of this letter agreement shall be deemed to be a continuing waiver in the future or a waiver of any subsequent default or a waiver of any other provision, condition, or requirement hereof, nor shall any delay or omission of either party to exercise any right hereunder in any manner impair the exercise of any such right.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(f)<u>Construction</u>. The headings herein are for convenience only, do not constitute a part of this letter agreement and shall not be deemed to limit or affect any of the provisions hereof. The language used in this letter agreement will be deemed to be the language chosen by the parties to express their mutual intent, and no rules of strict construction will be applied against any party. This letter agreement shall be construed as if drafted jointly by the parties, and no presumption or burden of proof shall arise favoring or disfavoring any party by virtue of the authorship of any provisions of this letter agreement.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(g)<u>No Third-Party Beneficiaries</u>. This letter agreement is intended for the benefit of the parties hereto and their respective successors and permitted assigns and is not for the benefit of, nor may any provision hereof be enforced by, any other person, other than Investor Indemnitors.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(h)<u>Delivery by Facsimile or Electronic Transmission</u>. This letter agreement and any signed agreement or instrument entered into in connection with this letter agreement, and any amendments or waivers hereto or thereto, to the extent signed and delivered by means of a facsimile machine or by e-mail delivery of a ".pdf" format data file, shall be treated in all

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manner and respects as an original agreement or instrument and shall be considered to have the same binding legal effect as if it were the original signed version thereof delivered in person. No party hereto or to any such agreement or instrument shall raise the use of a facsimile machine or e-mail delivery of a ".pdf" format data file to deliver a signature to this letter agreement or any amendment hereto or the fact that any signature or agreement or instrument was transmitted or communicated through the use of a facsimile machine or e-mail delivery of a ".pdf" format data file as a defense to the formation of a contract and each party hereto forever waives any such defense.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(i)<u>Counterparts</u>. This letter agreement may be executed in two or more counterparts, all of which when taken together shall be considered one and the same agreement and shall become effective when counterparts have been signed by each party and delivered to the other party, it being understood that the parties need not sign the same counterpart.

**[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]**

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**FIRSTSUN CAPITAL BANCORP**

By:<u>&nbsp;&nbsp;&nbsp;&nbsp;/s/ Neal E. Arnold&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</u>

Name: Neal E. Arnold<br>Title: President & Chief Executive Officer

***[Signature Page to the Board Representative Letter Agreement]***

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Agreed and acknowledged as of the date first above written:

**CASTLE CREEK CAPITAL PARTNERS IX, LP**

By:<u>&nbsp;&nbsp;&nbsp;&nbsp;/s/ Tony Scavuzzo&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</u>

Name: Tony Scavuzzo<br>Title: Managing Principal

***[Signature Page to the Board Representative Letter Agreement]***

## Exhibit 99.1

Exhibit 99.1

**Affiliates of Castle Creek Capital Acquire $40 Million Equity Position From Legacy Stockholders in FirstSun Capital Bancorp**

SAN DIEGO and DENVER, December 4, 2025 — Castle Creek Capital, an alternative asset management firm focused on the financial services sector, with a specialization in the community banking industry, announced today that Castle Creek managed funds have acquired, from legacy stockholders, $40 million of common stock in FirstSun Capital Bancorp (the "Company" or "FirstSun"). In accordance with an agreement between affiliates of Castle Creek Capital and FirstSun, subject to satisfying all legal and regulatory requirements, it is expected that Spencer T. Cohn will join the Company's board of directors upon the earlier of (i) the closing of the Company's proposed merger with First Foundation Inc. ("First Foundation") and (ii) the 2026 annual meeting of the Company's stockholders. Castle Creek is now one of FirstSun's largest institutional stockholders, with a current ownership stake of approx. 4% as of December 4, 2025.

"The merger with First Foundation plays to CEO Neal Arnold's and CFO Rob Cafera's demonstrated strengths given the balance sheet re-positioning required to unlock First Foundation's underlying core franchise," said Spencer T. Cohn, Director at Castle Creek Capital. "This combination allows management to substantially improve the Company's already top-tier performance and also reduce its credit and liquidity risk profile given the complementary business mix and pristine asset quality at First Foundation. More importantly, we believe FirstSun's enhanced pro forma run-rate and more durable earnings stream presents significant upside for stockholders today," added Cohn.

"Working with sophisticated and experienced investors who share our values and drive for stockholder return continues to be a top priority for our team," said Neal Arnold, CEO and President of FirstSun. "Castle Creek is well-known to us, and we are thrilled to partner with them again as we expand our franchise and geographic reach. Castle Creek is one of the most reputable investors in the industry with a strong cultural fit with our team, and we believe their continued support validates the merits of the merger and our strategy. We look forward to continuing to work collaboratively with Castle Creek," added Arnold.

"As FirstSun has built a high quality, specialty bank on the foundation of our customer-centric community banking values, we have relied upon investors who understand the sector and what differentiates us to help fuel our growth", said Mollie Carter, Executive Chairman of FirstSun. "We are pleased to have Castle Creek formally join those ranks, and we look forward to their continued support and contributions into this next chapter of our story," added Carter.

"FirstSun's impressive leadership team has built a remarkable organization, and we are thrilled to continue our partnership with the Company. CEO Neal Arnold, CFO Rob Cafera and the entire FirstSun team are highly focused on continuing to deliver a best-in-class regional bank, as evidenced by the Company's consistent, industry-leading profitability and growth. Our longstanding relationship with this proven management team solidifies our conviction in the Company's plan to drive substantial value creation for stockholders. We look forward to continued collaboration with the Company," said Tony Scavuzzo, Managing Principal at Castle Creek Capital.

**About FirstSun Capital Bancorp**

FirstSun Capital Bancorp (NASDAQ: FSUN), headquartered in Denver, Colorado, is the financial holding company for Sunflower Bank, N.A., headquartered in Dallas, Texas, which operates as Sunflower Bank and First National 1870. Sunflower Bank provides a full range of relationship-focused services to meet personal, business and wealth management financial objectives, with depository branches in seven states and mortgage capabilities in 43 states. FirstSun had total consolidated assets of $8.5 billion as September 30, 2025.

First National 1870 is a division of Sunflower Bank, N.A. To learn more, visit ir.firstsuncb.com or SunflowerBank.com.

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Exhibit 99.1

**About Castle Creek Capital**

Castle Creek Capital (the "Firm") is an alternative asset management firm focused on the community banking industry. Located in San Diego, California and Dallas, Texas, the Firm has been a leading investor in community banking since its inception in 1990, having raised and managed nine private equity funds and multiple special situations funds. Castle Creek has more than 100 combined years of industry experience—five decades operating banks and another five investing in them—which allows the Firm to bring differentiated insight to its portfolio companies.

Sidley Austin LLP acted as legal counsel to Castle Creek Capital.

Nelson Mullins Riley & Scarborough LLP acted as legal counsel to FirstSun Capital Bancorp.

**CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS**

Statements included in this communication which are not historical in nature are intended to be, and hereby are identified as, "forward-looking statements" within the meaning, and subject to the protections of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements other than statements of historical fact are forward-looking statements. Examples of forward-looking statements include, but are not limited to, statements regarding the expected benefits of FirstSun's proposed merger (the "merger" or the "proposed transaction") with First Foundation Inc. ("First Foundation") and the proposed balance sheet re-positioning in connection with the merger. These statements reflect management's current expectations and are not guarantees of future performance. Words such as "may," "will," "believe," "anticipate," "expect," "intend," "opportunity," "continue," "should," and "could" and variations of such words and similar expressions are intended to identify such forward-looking statements. Forward-looking statements are subject to risks, uncertainties and assumptions that are difficult to predict with regard to timing, extent, likelihood and degree of occurrence, which could cause actual results to differ materially from anticipated results. Such risks, uncertainties and assumptions, include, among others, the following:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;the failure to obtain necessary regulatory approvals when expected or at all (and the risk that such approvals may result in the imposition of conditions that could adversely affect the combined company or the expected benefits of the proposed transaction);

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;the failure of First Foundation or FirstSun to obtain the required stockholder approval, or the failure of either party to satisfy any of the other closing conditions on a timely basis or at all;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;the occurrence of any event, change or other circumstances that could give rise to the right of one or both of the parties to terminate the merger agreement;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;the possibility that the proposed transaction, including the balance sheet re-positioning strategy, will not be completed as planned, including the anticipated benefits of the proposed transaction, including the balance sheet re-positioning strategy;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;changes in global financial markets and economies and general market conditions, such as interest rates, foreign exchange rates, or stock, commodity, credit or asset valuations or volatility;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;diversion of management's attention from ongoing business operations and opportunities;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;potential adverse reactions or changes to business or employee relationships, including those resulting from the announcement or completion of the proposed transaction;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;the outcome of any legal proceedings that may be instituted against FirstSun or First Foundation;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;the risk that the cost savings and synergies expected from the proposed transaction may not be realized or may take longer than anticipated to be realized;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;the risk that integration of FirstSun's and First Foundation's respective businesses may be materially delayed or more costly or difficult than expected, including as a result of unexpected factors or events;

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Exhibit 99.1

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;changes to tax legislation and their potential effects on the accounting for the merger;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;the possibility of dilution to existing stockholders resulting from the issuance of additional shares in connection with the proposed transaction;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;the possibility that the combined company may be subject to additional regulatory requirements as a result of the merger or expansion of its business operations; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;•&nbsp;&nbsp;&nbsp;&nbsp;other factors that may affect future results of FirstSun or First Foundation including changes in asset quality and credit risk; the inability to sustain revenue and earnings growth; changes in interest rates and capital markets; inflation; customer borrowing, repayment, investment and deposit practices; the impact, extent and timing of technological changes; capital management activities; and actions of the Federal Reserve Board and legislative and regulatory actions and reforms.

Further information regarding additional factors that could affect the forward-looking statements can be found in the cautionary language included under the headings "Cautionary Note Regarding Forward-Looking Statements" (in the case of FirstSun), "Forward-Looking Statements" (in the case of First Foundation), and "Risk Factors" in FirstSun's and First Foundation's Annual Reports on Form 10-K for the year ended December 31, 2024 (available at <u>[https://www.sec.gov/ix?doc=/Archives/edgar/data/0001709442/000170944225000008/fcb-20241231.htm](https://www.sec.gov/Archives/edgar/data/1709442/000170944225000008/fcb-20241231.htm)</u> and <u>[https://www.sec.gov/ix?doc=/Archives/edgar/data/0001413837/000155837025003129/ffwm-20241231x10k.htm](https://www.sec.gov/Archives/edgar/data/1413837/000155837025003129/ffwm-20241231x10k.htm)</u>, respectively), and other documents subsequently filed by FirstSun and First Foundation with the Securities and Exchange Commission (the "SEC"). FirstSun disclaim any obligation to update or revise any forward-looking statements contained in this communication, which speak only as of the date hereof, whether as a result of new information, future events or otherwise, except as required by law.

**Additional Information About the Merger and Where to Find It**

This communication contains statements regarding the proposed transaction between FirstSun and First Foundation. In connection with the proposed transaction, FirstSun will file a registration statement on Form S-4 with the SEC to register FirstSun's shares that will be issued to First Foundation's stockholders in connection with the merger. The registration statement will include a joint proxy statement of FirstSun and First Foundation and a prospectus of FirstSun, as well as other relevant documents concerning the proposed transaction. When available, the joint proxy statement/prospectus will be sent to stockholders of FirstSun and First Foundation in connection with the proposed transaction. INVESTORS ARE URGED TO READ THE REGISTRATION STATEMENT AND THE JOINT PROXY STATEMENT/PROSPECTUS REGARDING THE MERGER WHEN IT BECOMES AVAILABLE AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC, AS WELL AS ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC IN CONNECTION WITH THE TRANSACTION OR INCORPORATED BY REFERENCE INTO THE REGISTRATION STATEMENT ON FORM S-4 AND THE JOINT PROXY STATEMENT/PROSPECTUS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION REGARDING FIRSTSUN, FIRST FOUNDATION, THE TRANSACTION AND RELATED MATTERS.

This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of such jurisdiction.

A free copy of the joint proxy statement/prospectus, when it becomes available, as well as other documents filed with the SEC by FirstSun or First Foundation may be obtained at the SEC's Internet site at http://www.sec.gov. Investors and security holders may also obtain free copies of the documents filed with the SEC by (i) FirstSun on its website at https://ir.firstsuncb.com/overview/default.aspx under the Financials tab and then under the SEC Filings option, and (ii) First Foundation on its website at https://investor.ff-inc.com/investor-home/default.aspx under the Financials tab and then under the SEC Filings option.

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Exhibit 99.1

**Participants in the Solicitation**

FirstSun, First Foundation and certain of their directors and executive officers may be deemed participants in the solicitation of proxies from stockholders of FirstSun or First Foundation in connection with the proposed transaction. Information regarding the directors and executive officers of FirstSun and First Foundation and other persons who may be deemed participants in the solicitation of the stockholders of FirstSun or First Foundation in connection with the proposed transaction will be included in the joint proxy statement/prospectus, which will be filed by FirstSun with the SEC. Information about the directors and officers of FirstSun and their ownership of FirstSun common stock can be found in FirstSun's definitive proxy statement in connection with its 2025 annual meeting of stockholders, including under the headings "Director Experience", "Biographical Information for Executive Officers", "Certain Relationships and Related Party Transactions", "Security Ownership of Certain Beneficial Owners and Management", "Executive Compensation", and "Compensation of Directors for Fiscal Year 2024", as filed with the SEC on March 21, 2025 and available at <u>[https://www.sec.gov/ix?doc=/Archives/edgar/data/0001709442/000170944225000020/fcb-20250321.htm](https://www.sec.gov/Archives/edgar/data/1709442/000170944225000020/fcb-20250321.htm)</u>, and other documents subsequently filed by FirstSun with the SEC, including on Statements of Change in Ownership on Form 4 filed with the SEC, available at https://www.sec.gov/edgar/browse/?CIK=1709442&owner=exclude. Information about the directors and officers of First Foundation and their ownership of First Foundation common stock can be found in First Foundation's definitive proxy statement in connection with its 2025 annual meeting of stockholders, including under the headings "Security Ownership of Certain Beneficial Owners and Management", "Election of Directors (Proposal No. 1)", "Advisory Vote on the Compensation of the Company's Named Executive Officers (Proposal No. 4)", "Compensation Committee Report", and "Certain Relationships and Related Party Transactions" as filed with the SEC on April 17, 2025 and available at <u>[https://www.sec.gov/ix?doc=/Archives/edgar/data/0001413837/000110465925036041/tm252563-3_def14a.htm](https://www.sec.gov/Archives/edgar/data/1413837/000110465925036041/tm252563-3_def14a.htm)</u>, and other documents subsequently filed by First Foundation with the SEC, including on Statements of Change in Ownership on Form 4 filed with the SEC, available at https://www.sec.gov/edgar/browse/?CIK=1413837&owner=exclude. Additional information regarding the interests of participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will be included in the joint proxy statement/prospectus and other relevant documents regarding the proposed merger filed with the SEC when they become available. You may obtain free copies of these documents through the website maintained by the SEC at https://www.sec.gov.

**Contacts**

Ed Jacques

Director of Investor Relations & Business Development, FirstSun

Investor.Relations@firstsuncb.com

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