As filed with the Securities and Exchange Commission on May 31, 2019

Registration No. 333-

UNITED STATES SECURITIES AND EXCHANGE
COMMISSION

WASHINGTON, D.C. 20549

FORM S-8

REGISTRATION STATEMENT UNDER
THE SECURITIES ACT OF 1933

IRONWOOD PHARMACEUTICALS, INC.

(Exact Name of Registrant as Specified in its Charter)

Delaware

(State or Other Jurisdiction of Incorporation or Organization)

04-3404176

(I.R.S. Employer Identification Number)

301 Binney Street, Cambridge, MA 02142

(Address of Principal Executive Offices) (Zip Code)

Amended and Restated 2010 Employee Stock Purchase Plan

(Full Title of the Plan)

Gina Consylman
Chief Financial Officer
301 Binney Street
Cambridge, Massachusetts 02142

(Name and Address of Agent for Service)

(617) 621-7722

(Telephone Number, Including Area Code, of Agent for Service)

Please send copies of all communications to:

Paul M. Kinsella

Ropes & Gray LLP

Prudential Tower

800 Boylston Street
Boston, Massachusetts 02199-3600
(617) 951-7000

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer x	Accelerated filer o

Non-accelerated filer o	Smaller reporting company o

(Do not check if a smaller reporting company)

	Emerging growth company o

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 7(a)(2)(B) of the Securities Act. o

CALCULATION OF REGISTRATION FEE


Title of Securities to be Registered	Amount to be Registered (1)	Proposed Maximum Offering Price Per Share (2)		Proposed Maximum Aggregate Offering Price (2)		Amount of Registration Fee
Class A Common Stock, $0.001 par value per share	1,000,000	$	10.77	$	10,770,000.00	$	1,305.32

(1) This registration statement on Form S-8 (this “Registration Statement”) covers an aggregate of 1,000,000 shares of the Registrant’s Class A Common Stock, par value $0.001 per share (the “Common Stock”), that may be issued under the employee stock purchase plan identified above (the “Plan”). In addition, pursuant to Rule 416(a) under the Securities Act of 1933, as amended (the “Securities Act”), this Registration Statement also covers such additional shares of Common Stock as may be issued pursuant to the provisions of the Plan to which this Registration Statement relates.

(2) Pursuant to Rules 457(c) and 457(h)(1) under the Securities Act, the proposed maximum offering price per share and the maximum aggregate offering price for the shares have been calculated solely for the purpose of computing the registration fee on the basis of the average high and low prices of the Common Stock as reported by the Nasdaq Global Select Market, which were $10.97 and $10.57, respectively, on May 29, 2019.

EXPLANATORY NOTE

The Registrant increased the number of shares of its Common Stock available for issuance under its Amended and Restated 2010 Employee Stock Purchase Plan by 1,000,000 shares. Pursuant to Instruction E to Form S-8, the Registrant incorporates by reference, except to the extent supplemented, amended or superseded by the information set forth herein, into this Registration Statement the entire contents of its Registration Statement on Form S-8 (File No. 333-165230) filed with the Securities and Exchange Commission (the “SEC”) on March 5, 2010.

Item 8. Exhibits.

Exhibit		Description
4.1		Eleventh Amended and Restated Certificate of Incorporation. Filed as Exhibit 3.1 to the Annual Report on Form 10-K filed with the SEC on March 30, 2010.

4.2		Certificate of Amendment of Eleventh Amended and Restated Certificate of Incorporation. Filed as Exhibit 3.1 to the Current Report on Form 8-K filed with the SEC on May 31, 2019.

4.3		Fifth Amended and Restated Bylaws. Filed as Exhibit 3.2 to the Annual Report on Form 10-K filed with the SEC on March 30, 2010.

4.4		Amended and Restated 2010 Employee Stock Purchase Plan. Filed as Exhibit 10.4 to Form 10-K filed with the SEC on February 21, 2013.

4.5		Specimen Class A common stock certificate. Filed as Exhibit 4.1 to the Registration Statement on Form S-1 filed with the SEC on January 20, 2010.

5.1		Opinion of Ropes & Gray LLP. Filed herewith.

23.1		Consent of Ropes & Gray LLP (included in Opinion filed as Exhibit 5.1).

23.2		Consent of Independent Registered Public Accounting Firm. Filed herewith.

24.1		Power of Attorney (included on the signature page of this Registration Statement). Filed herewith.

SIGNATURES

Pursuant to the requirements of the Securities Act, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this registration statement on Form S-8 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Cambridge, Commonwealth of Massachusetts, on May 31, 2019.

	IRONWOOD PHARMACEUTICALS, INC.

	By:	/s/ Mark Mallon
		Mark Mallon
		Chief Executive Officer

POWER OF ATTORNEY

Each person whose signature appears below hereby constitutes and appoints Mark Mallon, Gina Consylman, Halley E. Gilbert and Conor Kilroy, and each of them singly, his or her true and lawful attorney-in-fact and agent with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments (including post-effective amendments) to this registration statement on Form S-8 of Ironwood Pharmaceuticals, Inc., and to file the same, with all exhibits thereto, and other documents in connection therewith, with the SEC, granting unto said attorneys-in-fact and agents full power and authority to be done in and about the premises, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that said attorneys-in-fact and agents, or their substitutes, may lawfully do or cause to be done by virtue hereof.

Pursuant to the requirements of the Securities Act, this registration statement on Form S-8 has been signed by the following persons in the capacities identified and on May 31, 2019:

Signature		Title


/s/ Mark Mallon		Chief Executive Officer and Director
Mark Mallon		(Principal Executive Officer)


/s/ Gina Consylman		Chief Financial Officer
Gina Consylman		(Principal Financial Officer and Principal Accounting Officer)


/s/ Julie H. McHugh		Chair of the Board
Julie H. McHugh


/s/ Mark Currie		Director
Mark Currie


/s/ Andrew Dreyfus		Director
Andrew Dreyfus


/s/ Jon Duane		Director
Jon Duane

/s/ Marla Kessler		Director
Marla Kessler


/s/ Catherine Moukheibir		Director
Catherine Moukheibir


/s/ Lawrence S. Olanoff		Director
Lawrence S. Olanoff


/s/ Edward P. Owens		Director
Edward P. Owens