PSXP Phillips 66 Partners LP

As filed with the Securities and Exchange Commission on March 9, 2022

Registration No. 333-234334

Registration No. 333-221353

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

POST-EFFECTIVE AMENDMENT TO

FORM S-3

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

2331 CityWest Boulevard

Houston, Texas 77042

(855) 283-9237

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Vanessa Allen Sutherland

Vice President, General Counsel and Secretary

2331 CityWest Boulevard

Houston, Texas 77042

(855) 283-9237

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copy to:

William N. Finnegan IV

Thomas G. Brandt

Latham & Watkins LLP

811 Main Street, Suite 3700

Houston, Texas 77002

(713) 546-5400

Approximate date of commencement of proposed sale to the public: Not applicable

If the only securities being registered on this Form are being offered pursuant to dividend or interest reinvestment plans, please check the following box.  ☐

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, other than securities offered only in connection with dividend or interest reinvestment plans, check the following box.  ☐

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering.  ☐

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(e) under the Securities Act, check the following box.  ☐

If this Form is a post-effective amendment to a registration statement filed pursuant to General Instruction I.D. filed to register additional securities or additional classes of securities pursuant to Rule 413(b) under the Securities Act, check the following box.  ☐

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

EXPLANATORY NOTE — DEREGISTRATION OF SECURITIES

This Post-Effective Amendment relates to the following Registration Statements on Form S-3 (collectively, the “Registration Statements”), originally filed by Phillips 66 Partners LP, a Delaware limited partnership (the “Partnership”), with the Securities and Exchange Commission:

On October 26, 2021, Phillips 66, a Delaware corporation (“Parent”) and the indirect owner of Common Units representing approximately 70.2% of the total Common Units and Series A preferred units representing limited partner interests in the Partnership, voting together as a single class on an as-converted basis and outstanding prior to completion of the Merger (as defined herein), caused its indirect, wholly owned subsidiary Phillips 66 Project Development Inc., a Delaware corporation (“P66 PDI”), to deliver a written consent approving the adoption of that certain Agreement and Plan of Merger, dated as of October 26, 2021 (the “Merger Agreement”), by and among Parent, the Partnership, Phillips 66 Partners GP LLC, a Delaware limited liability company and the general partner of the Partnership, Phillips 66 Company, a Delaware corporation and wholly owned subsidiary of Parent (“P66 Company”), P66 PDI and Phoenix Merger Sub LLC, a Delaware limited liability company and jointly owned subsidiary of P66 Company and P66 PDI (“Merger Sub”), and the transactions contemplated by the Merger Agreement, including the Merger (as defined below), for and on behalf of the limited partners of the Partnership. At the Effective Time (as defined below) of the Merger, pursuant to the terms of the Merger Agreement, each outstanding Common Unit, other than those held by Parent or any of its subsidiaries, was converted into the right to receive 0.500 of a share of Parent’s common stock, par value $0.01, and Merger Sub merged with and into the Partnership (the “Merger”), with the Partnership continuing and surviving as an indirect, wholly owned subsidiary of Parent following the Merger.

The Merger was consummated on March 9, 2022 (the “Effective Time”), pursuant to the Certificate of Merger filed with the Secretary of State of the State of Delaware. In connection with the completion of the Merger, the Partnership terminated all offerings of securities pursuant to the Registration Statements. In accordance with undertakings made by the Partnership in the Registration Statements to remove from registration, by means of a post-effective amendment, any of the securities that had been registered for issuance that remain unsold at the termination of such offering, the Partnership hereby removes from registration all of such securities of the Partnership registered but unsold under the Registration Statements as of the Effective Time.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended (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-3 and has duly caused this Post-Effective Amendment to the Registration Statements to be signed on its behalf by the undersigned, thereunto duly authorized, in the city of Houston, Texas, on March 9, 2022.

Note: Pursuant to Rule 478 of the Securities Act of 1933, as amended, no other person is required to sign this Post-Effective Amendment to the Registration Statements.