As filed with the Securities and Exchange Commission on November 5, 2021

Registration No. 333-260396

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

POST-EFFECTIVE AMENDMENT NO. 1

FORM S-8

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Portillo’s Inc.

(Exact name of registrant as specified in its charter)

Portillo’s, Inc. 2021 Equity Incentive Plan

(Full title of the plan)

Susan B. Shelton

General Counsel and Secretary

2001 Spring Road, Suite 400

Oak Brook, IL 60523

(630) 354-3773

(Name, Address, Including Zip Code, and Telephone Number, Including Area Code, of Agent for Service of Process)

Copies to:

Alexander D. Lynch

Merritt S. Johnson

Weil, Gotshal & Manges LLP

767 Fifth Avenue

New York, NY 10153

(212) 310-8000 (Phone)

(212) 310-8007 (Fax)

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.

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.  ☐

EXPLANATORY NOTE

This Post-Effective Amendment No. 1 relates to the Registrant’s Registration Statement on Form S-8 (File No. 333-260396), initially filed by the Registrant on October 21, 2021 (the “Registration Statement”). The Registrant is filing this Post-Effective Amendment No. 1 for the sole purpose of correcting the allocation of all shares of the Registrant’s Class A common stock registered pursuant to the Registration Statement to the Portillo’s Inc. 2021 Equity Incentive Plan (the “2021 Plan”). The Registration Statement incorrectly indicated that 6,416,865 shares of Class A common stock would be allocated and available for issuance under the 2014 Equity Incentive Plan (the “2014 Plan”). However, in connection with the Registrant’s initial public offering, each outstanding option previously granted under the 2014 Plan was substituted for an option to purchase a number of shares of the Registrant’s Class A common stock under the 2021 Plan. Therefore, all 13,564,914 shares of Class A common stock registered pursuant to the Registration Statement should be allocated to the 2021 Plan. The total number of shares registered is unchanged and the requisite filing fee has been fully paid.

This Post-Effective Amendment No. 1 does not modify any provision of Part I or Part II of the Registration Statement other than as set forth below.

PART II

INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

The exhibits to this Registration Statement are listed in the Exhibit Index below and are incorporated by reference herein.

Exhibit Index

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, 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 Post-Effective Amendment No. 1 to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Oak Brook, State of Illinois, on November 5, 2021.

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed by the following persons in the capacities indicated on November 5, 2021.