As filed with the Securities and Exchange Commission on March 18, 2015

Registration No. 2-43384

811-02280

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933	x
Pre-Effective Amendment No.	¨
Post-Effective Amendment No. 59	x

and/or

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF 1940	x
Amendment No. 51	x

(Check appropriate box or boxes)

PUTNAM CONVERTIBLE SECURITIES FUND

(Exact Name of Registrant as Specified in Charter)

One Post Office Square, Boston, Massachusetts 02109

(Address of Principal Executive Offices) (Zip Code)

Registrant’s Telephone Number, including Area Code

(617) 292-1000

It is proposed that this filing will become effective (check appropriate box)

¨ immediately upon filing pursuant to paragraph (b)

x on February 28, 2015 pursuant to paragraph (b)

¨ 60 days after filing pursuant to paragraph (a)(1)

¨ on (date) pursuant to paragraph (a)(1)

¨ 75 days after filing pursuant to paragraph (a)(2)

¨ on (date) pursuant to paragraph (a)(2) of Rule 485.

If appropriate, check the following box:

¨ this post-effective amendment designates a new effective date for a previously filed post-effective amendment.

ROBERT T. BURNS, Vice President

PUTNAM CONVERTIBLE SECURITIES FUND

One Post Office Square

Boston, Massachusetts 02109

(Name and address of agent for service)

Copy to:

BRYAN CHEGWIDDEN, Esquire

ROPES & GRAY LLP

1211 Avenue of the Americas

New York, New York 10036

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all of the requirements for effectiveness of this Registration Statement under Rule 485(b) under the Securities Act of 1933 and has duly caused this Amendment to its Registration Statement to be signed on its behalf by the undersigned, duly authorized, in the City of Boston, and The Commonwealth of Massachusetts, on the 18^th day of March, 2015.

	Putnam Convertible Securities Fund
By: /s/	Jonathan S. Horwitz, Executive Vice President, Principal Executive Officer and Compliance Liaison

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

Signature	Title
Jameson A. Baxter*	Chair, Board of Trustees
Robert L. Reynolds*	President and Trustee
Jonathan S. Horwitz*	Executive Vice President, Principal Executive Officer and Compliance Liaison
Steven D. Krichmar*	Vice President and Principal Financial Officer
Janet C. Smith*	Vice President, Principal Accounting Officer and Assistant Treasurer
Liaquat Ahamed*	Trustee
Ravi Akhoury*	Trustee
Barbara M. Baumann*	Trustee
Charles B. Curtis*	Trustee
Robert J. Darretta*	Trustee
Katinka Domotorffy*	Trustee
John A. Hill*	Trustee

Paul L. Joskow*	Trustee
Kenneth R. Leibler*	Trustee
Robert E. Patterson*	Trustee
George Putnam, III*	Trustee
W. Thomas Stephens*	Trustee

By: /s/ Jonathan S. Horwitz, as Attorney-in-Fact
March 18, 2015

*Signed pursuant to power of attorney filed in Post-Effective Amendment No. 53 to the Registrant’s Registration Statement on February 26, 2013.

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EXHIBIT INDEX

XBRL Instance Document	Ex-101.ins
XBRL Taxonomy Extension Schema Document	Ex-101.sch
XBRL Taxonomy Extension Calculation Linkbase Document	Ex-101.cal
XBRL Taxonomy Extension Labels Linkbase	Ex-101.lab
XBRL Taxonomy Extension Presentation Linkbase Document	Ex-101.pre
XBRL Taxonomy Extension Definition Linkbase	Ex-101.def

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