8-K

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):

May 28, 2025

IRONWOOD PHARMACEUTICALS, INC.

(Exact name of registrant as specifiedin its charter)

(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:

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

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 3.01 Notice of Delisting or Failure to Satisfy a ContinuedListing Rule or Standard; Transfer of Listing.

On May 28, 2025, Ironwood Pharmaceuticals, Inc. (the “Company”) received a deficiency letter from the Listing Qualifications Department (the “Staff”) of The Nasdaq Stock Market LLC (“Nasdaq”) notifying the Company that, for the last 30 consecutive business days, the bid price for the Company’s Class A common stock, par value $0.001 per share (the “Common Stock”) had closed below the $1.00 per share minimum bid price requirement for continued inclusion on the Nasdaq Global Select Market pursuant to Nasdaq Listing Rule 5450(a)(1) (the “Minimum Bid Price Requirement”). The deficiency letter has no immediate effect on the listing of the Company’s securities on Nasdaq.

In accordance with Nasdaq Listing Rule 5810(c)(3)(A) (the “Compliance Period Rule”), the Company has been provided a period of 180 calendar days, or until November 24, 2025 (the “Compliance Date”), to regain compliance with the Minimum Bid Price Requirement. If, at any time before the Compliance Date, the bid price for the Common Stock closes at $1.00 or more for a minimum of 10 consecutive business days as required under the Compliance Period Rule (unless the Staff exercises its discretion to extend this ten-day period pursuant to Nasdaq Listing Rule 5810(c)(3)(H)), the Staff will provide written notification to the Company that it has regained compliance with the Minimum Bid Price Requirement.

If the Company does not regain compliance with the Minimum Bid Price Requirement by the Compliance Date, the Company may be eligible for an additional 180 calendar day compliance period. To qualify, the Company would need to transfer the listing of the Common Stock to the Nasdaq Capital Market, provided that it meets certain requirements.

Should the Staff conclude that the Company will not be able to cure the deficiency, or should the Company determine not to submit an application for transfer to the Nasdaq Capital Market or notify the Staff of its intention to cure the deficiency, the Staff will provide written notification to the Company that the Common Stock will be subject to delisting. At that time, the Company may appeal the Staff’s delisting determination to a Nasdaq Listing Qualifications Panel (the “Panel”). However, there can be no assurance that, if the Company receives a delisting notice and appeals the delisting determination by the Staff to the Panel, such appeal would be successful.

The Company intends to monitor the closing bid price of the Common Stock and may, if appropriate, consider available options to regain compliance with the Minimum Bid Price Requirement. However, there can be no assurance that the Company will be able to regain compliance with the Minimum Bid Price Requirement.

Forward-Looking Statements

This Current Report contains forward-lookingstatements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements contained in this Current Reportthat do not relate to matters of historical fact should be considered forward-looking statements, including without limitation statementsregarding the Company’s ability to regain compliance with any applicable Nasdaq listing requirements; the Company’s eligibilityfor an additional 180 calendar day compliance period to comply with the minimum bid price requirement; and the expected timing of anyof the foregoing. Statements using words such as “expect”, “anticipate”, “believe”, “may”,“will” and similar terms are also forward-looking statements. These statements are neither promises nor guarantees, but involveknown and unknown risks, uncertainties and other important factors that may cause the Company’s actual results, performance or achievementsto be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements,including, but not limited to, the important factors discussed under the caption “Risk Factors” in the Company’s AnnualReport on Form 10-K for the year ended December 31, 2024 and other filings with the Securities and Exchange Commission. Except as requiredby law, the Company undertakes no obligations to make any revisions to the forward-looking statements contained in this Current Reportor to update them to reflect events or circumstances occurring after the date of this Current Report, whether as a result of new information,future developments or otherwise.

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.