As filed with the Securities and Exchange Commission on March 25, 2022

Securities Act File No. 333-57793

Investment Company Act of 1940 File No. 811-08839

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

And

REGISTRATION STATEMENT

UNDER

SPDR^® SERIES TRUST

(Exact Name of Registrant as Specified in Charter)

One Iron Street

Boston, Massachusetts 02110

(Address of Principal Executive Offices)

Registrant’s Telephone Number: (617) 664-1465

Sean O’Malley, Esq.

Senior Vice President and Deputy General Counsel

c/o SSGA Funds Management, Inc.

One Iron Street

Boston, Massachusetts 02210

(Name and Address of Agent for Service)

Copies to:

W. John McGuire, Esq.

Morgan, Lewis & Bockius LLP

1111 Pennsylvania Avenue, NW

Washington, DC 20004

It is proposed that this filing will become effective:

NOTE: This Post-Effective Amendment No. 285 to the Registrant’s Registration Statement on Form N-1A is being filed pursuant to paragraph (b)(1)(iii) of Rule 485 under the Securities Act of 1933, as amended (the “Securities Act”), solely for the purpose of delaying, until April 11, 2022, the effectiveness of Post-Effective Amendment No. 277 to the Registrant’s Registration Statement on Form N-1A, with respect to the SPDR MarketAxess Investment Grade 400 Corporate Bond ETF, which was filed pursuant to Rule 485(a) under the Securities Act on December 13, 2021 (the “Amendment”).

Part A. INFORMATION REQUIRED IN A PROSPECTUS

Part A is incorporated by reference to Part A of the Amendment.

Part B. INFORMATION REQUIRED IN A STATEMENT OF ADDITIONAL INFORMATION

Part B is incorporated by reference to Part B of the Amendment.

Part C.    OTHER INFORMATION

Part C is incorporated by reference to Part C of the Amendment.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, and the Investment Company Act of 1940, as amended, SPDR^® Series Trust, the Registrant, certifies that it meets all the requirements for effectiveness of this Registration Statement pursuant to Rule 485(b)(1)(iii) under the Securities Act of 1933, as amended, and has duly caused this Amendment to the Registration Statement to be signed on its behalf by the undersigned, thereunder duly authorized, in the City of Boston and the Commonwealth of Massachusetts on the 25^th day of March, 2022.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, this Amendment to the Registration Statement has been signed below by the following persons in the capacities and on the date indicated: