UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

Form 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15D-16 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of September, 2021

Commission File Number: 1-13368

POSCO

(Translation of registrant’s name into English)

POSCO Center, 440 Teheran-ro, Gangnam-gu, Seoul, Korea, 06194

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F  ☒                     Form 40-F  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ☐

Note: Regulation S-T Rule 101(b)(1) only permits the submission in paper of a Form 6-K if submitted solely to provide an attached annual report to security holders.

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ☐

Note: Regulation S-T Rule 101(b)(7) only permits the submission in paper of a Form 6-K if submitted to furnish a report or other document that the registrant foreign private issuer must furnish and make public under the laws of the jurisdiction in which the registrant is incorporated, domiciled or legally organized (the registrant’s “home country”), or under the rules of the home country exchange on which the registrant’s securities are traded, as long as the report or other document is not a press release, is not required to be and has not been distributed to the registrant’s security holders, and, if discussing a material event, has already been the subject of a Form 6-K submission or other Commission filing on EDGAR.

Result of Treasury Stock Disposal

1. Issuer and Address

2. Contents regarding Disposition Report

3. Information regarding Disposition

* Note: The above disposed amount is the exchange price of exchangeable bonds and the unit is the Korean Won (“KRW”).

* Please note that the above disposition of treasury stock was prepared with respect to the foreign currency exchangeable bonds issued by the Company on September 1, 2021, assuming that a total of 2,932,480 treasury stocks, which are the exchangeable stocks of the bonds, were requested for exchange on the same day.

* The actual details of disposition of treasury stock will be finalized at the time the exchange right of the exchangeable bond is exercised. Treasury stocks are currently deposited with the Korea Securities Depository.

* For details on issuance of the exchangeable bonds and decision on dispose of treasury stock, please refer to the Company’s SEC submissions which are Decision on Issuance of Exchangeable Bonds on August 27, 2021 and Decision on Disposal of Treasury Stock on August 20, 2021.

4. The Holding Status of Treasury Stock after Disposal

* As stated in “3. Information regarding Disposition”, a total of 2,932,480 treasury shares subject to exchange for exchangeable bonds are deemed to have been requested for exchange on the same day, and are excluded in the above “Number of Shares”.

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, thereunto duly authorized.