Stamps.com Inc. STMP, -3.46% shares jumped nearly 20% in after-hours trading Thursday after the online-postage company increased its annual forecast and beat diminished earnings expectations. Stamps.com reported third-quarter profit of $9.1 million, or 52 cents a share, on sales of $136.2 million, down from $143.5 million a year ago. After adjusting for stock-based compensation and other effects, the company reported earnings of $1.12 a share, down from $2.76 a share a year ago. Analysts on average expected adjusted earnings of 70 cents a share on revenue of 123.2 million, according to FactSet. The financial declines have followed a break-up with the U.S. Postal Service that slammed Stamps.com’s forecast and stock, but shares have bounced back of late after the company landed a deal with United Parcel Service Inc. UPS, +1.26% Stamps.com shored up its annual forecast as well, raising its revenue guidance range to $535 million to $565 million from $520 million-$560 million, and moving the bottom of its adjusted-earnings guidance from $3.60 a share to $3.85. Shares closed with a 3.5% decline at $80.82, then topped $95 in late trading.