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2026-02-25 2026-02-25

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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):

February 25, 2026

IRONWOOD

PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

Delaware

001-34620

04-3404176

(State or other jurisdiction

(Commission File Number)

(I.R.S.

Employer

of incorporation)

Identification Number)

100 Summer Street, Suite 2300

Boston, Massachusetts

02110

(Address of principal

(Zip code)

executive offices)

(617) 621-7722

(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:

Title of each class Trading Symbol(s) Name of each exchange on which

registered

Class A common stock, $0.001 par value

IRWD

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 (§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 2.02 Results of Operations and Financial Condition.

On February 25, 2026, Ironwood Pharmaceuticals, Inc. issued a press release containing an update on its recent business activities as well as those for the quarter and year ended December 31, 2025. A copy of the press release is furnished as Exhibit 99.1 and is incorporated herein by reference.

The press release is being furnished pursuant to Item 2.02 of this Current Report on Form 8-K and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that Section, nor shall such document be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act except as shall be expressly set forth by specific reference in such filing.

Item 9.01 Financial Statements and Exhibits.

(d)  Exhibits.

Exhibit No.

Description

99.1

Ironwood Pharmaceuticals, Inc. Press Release dated February 25, 2026

104

The cover page from this Current Report on Form 8-K, formatted in Inline XBRL

SIGNATURES

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

Ironwood Pharmaceuticals, Inc.

Dated: February 25, 2026 By: /s/ Gregory Martini

Name: Gregory Martini

Title: Senior Vice President, Chief Financial Officer

false 0001446847

0001446847

2026-01-02 2026-01-02

iso4217:USD

xbrli:shares

iso4217:USD

xbrli:shares

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):

January 2, 2026

IRONWOOD

PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

Delaware

001-34620

04-3404176

(State or other jurisdiction

(I.R.S.

Employer

of incorporation)

(Commission File Number) Identification Number)

100 Summer Street, Suite 2300

Boston, Massachusetts

02110

(Address of principal

executive offices)

(Zip code)

(617) 621-7722

(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:

Title of each class Trading Symbol(s) Name of each exchange on which

registered

Class A common stock, $0.001 par value

IRWD

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 (§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 2.02 Results of Operations and Financial Condition.

On January 2, 2026, Ironwood Pharmaceuticals, Inc. (the “Company”) issued a press release containing an update on its recent business activities. A copy of the press release is furnished as Exhibit 99.1 and is incorporated herein by reference.

The press release is being furnished pursuant to Item 2.02 of this Current Report on Form 8-K and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that Section, nor shall such document be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act except as shall be expressly set forth by specific reference in such filing.

Item 9.01 Financial Statements and Exhibits.

(d)  Exhibits.

Exhibit No.

Description

99.1

Ironwood Pharmaceuticals, Inc. Press Release dated January 2, 2026

104

The cover page from this Current Report on Form 8-K, formatted in Inline XBRL

SIGNATURES

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

Ironwood Pharmaceuticals, Inc.

Dated: January 2, 2026 By: /s/ Gregory Martini

Name: Gregory Martini

Title: Senior Vice President, Chief Financial Officer