Form 8-K

8-K — SOUTHSIDE BANCSHARES INC

Accession: 0000705432-26-000093

Filed: 2026-05-20

Period: 2026-05-14

CIK: 0000705432

SIC: 6022 (STATE COMMERCIAL BANKS)

Item: Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year

Item: Submission of Matters to a Vote of Security Holders

Item: Financial Statements and Exhibits

Documents

8-K — sbsi-20260514.htm (Primary)

EX-3.1 (firstamendmenttorestatedce.htm)

XML — IDEA: XBRL DOCUMENT (R1.htm)

8-K

8-K (Primary)

Filename: sbsi-20260514.htm · Sequence: 1

sbsi-20260514

0000705432false12/31Chicago Stock Exchange, Inc.00007054322026-05-142026-05-140000705432sbsi:NYSETexasMember2026-05-142026-05-140000705432exch:XNYS2026-05-142026-05-14

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

May 14, 2026

Date of Report (Date of earliest event reported)

Southside Bancshares, Inc.

(Exact Name of Registrant as Specified in its Charter)

Texas 001-42396 75-1848732

(State or Other Jurisdiction of Incorporation) (Commission File Number) (IRS Employer Identification No.)

1201 S. Beckham Avenue, Tyler, TX 75701

(Address of Principal Executive Offices) (Zip Code)

Registrant's telephone number, including area code: (903) 531-7111

(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:

☐ 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:

Title of each class Trading Symbol Name of each exchange on which registered

Common stock, $1.25 par value SBSI New York Stock Exchange

NYSE Texas

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

Emerging growth company ☐

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.

☐

Item 5.03. Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On May 14, 2026, Southside Bancshares, Inc. (the “Company”) held its 2026 Annual Meeting of Shareholders (the “Annual Meeting”). At the Annual Meeting, the Company's shareholders approved an amendment to the Company’s Restated Certificate of Formation (the “Charter Amendment”) to authorize the issuance of up to 8,000,000 shares of flexible preferred stock. A detailed description of the Charter Amendment was set forth in Proposal Three in the Company’s 2026 Proxy Statement, filed with the Securities and Exchange Commission on March 25, 2026, which description is incorporated herein by reference and is qualified in its entirety by reference to the full text of the Charter Amendment filed herewith as Exhibit 3.1. The Charter Amendment became effective upon its filing with the Secretary of State of the State of Texas on May 19, 2026.

Item 5.07. Submission of Matters to a Vote of Security Holders.

A total of 26,767,647 shares of the Company's common stock were represented in person or by proxy at the Annual Meeting, or 89.99%, of the 29,743,585 shares outstanding as of the record date, March 16, 2026. The Company's shareholders voted on four proposals at the Annual Meeting, as set forth below.

Proposal 1 - Election of Directors

Shareholders approved the election of four directors to serve for three-year terms expiring at the 2029 Annual Meeting of Shareholders, one director to serve for a two-year term expiring at the 2028 Annual Meeting of Shareholders and one director to serve for a one-year term expiring at the 2027 Annual Meeting of Shareholders. Final results were as follows:

Term Expiring at the 2029 Annual Meeting: For Withheld Broker

Non-Votes

Lawrence L. Anderson, M.D. 23,379,541 629,316 2,758,790

Keith M. Donahoe 23,483,743 525,114 2,758,790

H. J. Shands, III 23,040,796 968,061 2,758,790

Preston L. Smith 22,770,922 1,237,935 2,758,790

Term Expiring at the 2028 Annual Meeting:

Jeb W. Jones 23,536,608 472,249 2,758,790

Term Expiring at the 2027 Annual Meeting:

Raymond C. McKinney, CPA 23,508,922 499,935 2,758,790

Proposal 2 - Say-on-Pay Vote

Shareholders approved, on a non-binding advisory basis, the compensation of the Company's named executive officers, as described in the Company's proxy statement. Final results were as follows:

For Against Abstain Broker

Non-Votes

22,322,893 1,546,713 139,251 2,758,790

Proposal 3 - Approval of Amendment to the Company's Restated Certificate of Formation

Shareholders approved an amendment to the Company's Restated Certificate of Formation to authorize the issuance of up to 8,000,000 shares of flexible preferred stock, as described in the Company's 2026 Proxy Statement. Final results were as follows:

For Against Abstain Broker

Non-Votes

21,818,160 2,013,911 176,786 2,758,790

Proposal 4 - Ratification of Appointment of Independent Registered Certified Public Accounting Firm

Shareholders ratified the appointment by the Company's Audit Committee of Ernst & Young LLP to serve as the Company's independent registered certified public accounting firm for the year ending December 31, 2026. Final results were as follows:

For Against Abstain Broker

Non-Votes

26,404,321 206,509 156,817 N/A

Item 9.01. Financial Statements and Exhibits.

(D)Exhibits. The following materials are furnished as exhibits to this Current Report on Form 8-K:

Exhibit

Number

Description of Exhibit

3.1

First Amendment to Restated Certificate of Formation of Southside Bancshares, Inc.

104 Cover Page Interactive Data File (embedded within the Inline XBRL document)

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.

Southside Bancshares, Inc.

Date: May 20, 2026 By: /s/ JULIE N. SHAMBURGER

Julie N. Shamburger, CPA

Chief Financial Officer

(Principal Financial Officer)

EX-3.1

Filename: firstamendmenttorestatedce.htm · Sequence: 2

Document

Exhibit 3.1

FIRST AMENDMENT

RESTATED

CERTIFICATE OF FORMATION

SOUTHSIDE BANCSHARES, INC.

Pursuant to the Texas Business Organizations Code (the “TBOC”), Southside Bancshares, Inc., a Texas corporation (the “Corporation”), hereby adopts this First Amendment to Restated Certificate of Formation (this “Amendment”) as set forth below:

1.The name of the Corporation is Southside Bancshares, Inc., a for-profit corporation.

2.The Corporation was formed as a for-profit corporation on August 11, 1982, and issued file number 61819600 by the Secretary of State of the State of Texas.

3.Article Four is amended and restated in its entirety to read as set forth below:

The total number of shares of capital stock that the Corporation shall have authority to issue is 88,000,000, consisting of: (i) 80,000,000 shares, $1.25 par value per share, of common stock (“Common Stock”) and (ii) 8,000,000 shares, no par value per share, of preferred stock (“Preferred Stock”).

The Preferred Stock may be issued from time to time in one or more series pursuant to a resolution or resolutions providing for such issue duly adopted by the Board of Directors (authority to do so being hereby expressly vested in the Board of Directors). The Board of Directors is further authorized, subject to limitations prescribed by law, to fix by resolution or resolutions and to set forth in a certification of designations filed pursuant to the Texas Business Organizations Code the designations, preferences, limitations, and relative rights of any wholly unissued series of Preferred Stock, including without limitation dividend rights, dividend rate, conversion rights, voting rights, rights and terms of redemption (including sinking fund provisions), redemption price or prices, and liquidation preferences of any such series, and the number of shares constituting any such series and the designation thereof, or any of the foregoing.

4.This Amendment has been made in accordance with the provisions of the TBOC. This Amendment has been approved in the manner required by the provisions of the TBOC and the governing documents of the Corporation.

5.This Amendment shall become effective when filed by the Secretary of State of the State of Texas.

The undersigned signs this document subject to the penalties imposed by law for the submission of a materially false or fraudulent instrument and certifies under penalty of perjury that the undersigned is authorized under the provisions of law governing the entity to execute the filing instrument.

SOUTHSIDE BANCSHARES, INC., a Texas corporation

By: /s/ Keith Donahoe

KEITH DONAHOE, President and Chief Executive Officer

XML — IDEA: XBRL DOCUMENT

XML

Filename: R1.htm · Sequence: 8

v3.26.1

Document and Entity Information Document

May 14, 2026

Document Information [Line Items]

Entity Central Index Key

0000705432

Document Type

8-K

Document Period End Date

May 14, 2026

Entity Registrant Name

Southside Bancshares, Inc.

Entity Emerging Growth Company

false

Entity Incorporation, State or Country Code

Entity File Number

001-42396

Entity Tax Identification Number

75-1848732

Entity Address, Address Line One

1201 S. Beckham Avenue,

Entity Address, City or Town

Tyler,

Entity Address, State or Province

Entity Address, Postal Zip Code

75701

City Area Code

903

Local Phone Number

531-7111

Written Communications

false

Soliciting Material

false

Pre-commencement Tender Offer

false

Pre-commencement Issuer Tender Offer

false

Amendment Flag

false

Current Fiscal Year End Date

--12-31

NEW YORK STOCK EXCHANGE, INC.

Document Information [Line Items]

Title of 12(b) Security

Common stock, $1.25 par value

Trading Symbol

SBSI

Security Exchange Name

NYSE

NYSE Texas

Document Information [Line Items]

Title of 12(b) Security

Common stock, $1.25 par value

Trading Symbol

SBSI

Security Exchange Name

CHX

- Definition

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

+ References

No definition available.

+ Details

Name:

dei_AmendmentFlag

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Area code of city

+ References

No definition available.

+ Details

Name:

dei_CityAreaCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

End date of current fiscal year in the format --MM-DD.

+ References

No definition available.

+ Details

Name:

dei_CurrentFiscalYearEndDate

Namespace Prefix:

dei_

Data Type:

xbrli:gMonthDayItemType

Balance Type:

Period Type:

duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:

dei_DocumentInformationLineItems

Namespace Prefix:

dei_

Data Type:

xbrli:stringItemType

Balance Type:

Period Type:

duration

- Definition

For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

+ References

No definition available.

+ Details

Name:

dei_DocumentPeriodEndDate

Namespace Prefix:

dei_

Data Type:

xbrli:dateItemType

Balance Type:

Period Type:

duration

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

+ References

No definition available.

+ Details

Name:

dei_DocumentType

Namespace Prefix:

dei_

Data Type:

dei:submissionTypeItemType

Balance Type:

Period Type:

duration

- Definition

Address Line 1 such as Attn, Building Name, Street Name

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine1

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the City or Town

+ References

No definition available.

+ Details

Name:

dei_EntityAddressCityOrTown

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Code for the postal or zip code

+ References

No definition available.

+ Details

Name:

dei_EntityAddressPostalZipCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the state or province.

+ References

No definition available.

+ Details

Name:

dei_EntityAddressStateOrProvince

Namespace Prefix:

dei_

Data Type:

dei:stateOrProvinceItemType

Balance Type:

Period Type:

duration

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityCentralIndexKey

Namespace Prefix:

dei_

Data Type:

dei:centralIndexKeyItemType

Balance Type:

Period Type:

duration

- Definition

Indicate if registrant meets the emerging growth company criteria.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityEmergingGrowthCompany

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

+ References

No definition available.

+ Details

Name:

dei_EntityFileNumber

Namespace Prefix:

dei_

Data Type:

dei:fileNumberItemType

Balance Type:

Period Type:

duration

- Definition

Two-character EDGAR code representing the state or country of incorporation.

+ References

No definition available.

+ Details

Name:

dei_EntityIncorporationStateCountryCode

Namespace Prefix:

dei_

Data Type:

dei:edgarStateCountryItemType

Balance Type:

Period Type:

duration

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityRegistrantName

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityTaxIdentificationNumber

Namespace Prefix:

dei_

Data Type:

dei:employerIdItemType

Balance Type:

Period Type:

duration

- Definition

Local phone number for entity.

+ References

No definition available.

+ Details

Name:

dei_LocalPhoneNumber

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 13e

-Subsection 4c

+ Details

Name:

dei_PreCommencementIssuerTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14d

-Subsection 2b

+ Details

Name:

dei_PreCommencementTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Title of a 12(b) registered security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b

+ Details

Name:

dei_Security12bTitle

Namespace Prefix:

dei_

Data Type:

dei:securityTitleItemType

Balance Type:

Period Type:

duration

- Definition

Name of the Exchange on which a security is registered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection d1-1

+ Details

Name:

dei_SecurityExchangeName

Namespace Prefix:

dei_

Data Type:

dei:edgarExchangeCodeItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14a

-Subsection 12

+ Details

Name:

dei_SolicitingMaterial

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Trading symbol of an instrument as listed on an exchange.

+ References

No definition available.

+ Details

Name:

dei_TradingSymbol

Namespace Prefix:

dei_

Data Type:

dei:tradingSymbolItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Securities Act

-Number 230

-Section 425

+ Details

Name:

dei_WrittenCommunications

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Details

Name:

dei_EntityListingsExchangeAxis=exch_XNYS

Namespace Prefix:

Data Type:

Balance Type:

Period Type:

- Details

Name:

dei_EntityListingsExchangeAxis=sbsi_NYSETexasMember

Namespace Prefix:

Data Type:

Balance Type:

Period Type: