STAMPS.COM ANNOUNCES CLOSE OF ITS FOLLOW-ON PUBLIC OFFERING AND EXERCISE OF UNDERWRITER’S OVER-ALLOTMENT OPTION

Final Phase of Previously Announced Investment by AOL Also Completed

SANTA MONICA, Calif. – December 13, 1999 – Stamps.com™ (Nasdaq: STMP) today announced that its follow-on public offering, which closed on December 10, 1999, resulted in net proceeds of $309.1 million through the sale of five million shares of Stamps.com common stock. Stamps.com also announced that the underwriters have exercised an option to purchase 750,000-shares to cover over-allotments, which will result in additional net proceeds to Stamps.com of $46.3 million. The over-allotment shares are expected to be delivered to the underwriters on December 15, 1999. The company also announced today that America Online, Inc. has completed the second and final phase of its previously announced multi-million dollar investment in Stamps.com. The investment is part of the alliance announced by the two companies in October 1999. The alliance also established Stamps.com the exclusive provider of Internet Postage™ on AOL, Netscape, and CompuServe branded CD-ROMs, and as the premier online provider of postage software available within key areas across several AOL brands.

Stamps.com expects to use the proceeds from the public offering and the AOL investment for working capital and general corporate purposes, including expansion of its marketing and distribution partnerships, advertising, and brand promotion and technology development. The public offering was managed by Goldman, Sachs & Co., Salomon Smith Barney Inc., BancBoston Robertson Stephens Inc., Thomas Weisel Partners LLC and Volpe Brown Whelan & Company, LLC. A copy of the Prospectus relating to the public offering may be obtained from the Prospectus Department of Goldman, Sachs & Co., at 85 Broad Street, New York, NY 10004, 212-902-1000, when available. The registration statement can also be viewed on the Internet.

About Stamps.com

Stamps.com offers a convenient, cost-effective and easy-to-use service for purchasing and printing postage over the Internet. Its core service is approved by the US Postal Service and is currently the only commercially available offering that requires no additional hardware to purchase and print postage; the user’s existing PC, printer and Internet setup are sufficient. Through partnerships with major companies like America Online, IBM, Microsoft, Office Depot, Quicken.com and 3M, Stamps.com targets the small office/home office and consumer markets. More information about the company can be found at sdcmainprod.wpengine.com.

“Safe Harbor” Statement under the Private Securities Litigation Reform Act of 1995: This release may contain forward-looking statements that involve risks and uncertainties. Important factors, which could cause actual results to differ materially from those in the forward-looking statements, are detailed in filings with the Securities and Exchange Commission made from time to time by Stamps.com, including its Form 10-Q for the quarter ended September 30, 1999 and its registration statement on Form S-1, as amended, that was declared effective by the SEC on December 6, 1999. Internet Postage, Stamps.com and the Stamps.com logo are trademarks of Stamps.com Inc. All other brands and names are property of their respective owners.