What happened

Shares of Stamps.com (NASDAQ:STMP) soared as much as 16.7% higher on Thursday, following the release of solid fourth-quarter results. At 2 p.m. EST, the stock had settled down to a smaller but still impressive 11.7% gain.

So what

The shipping software and online postage specialist saw top-line revenue rise 25% year over year, landing at $132.5 million. Adjusted earnings surged 71% higher over the same period, stopping at $4.68 per diluted share. Analysts would have settled for earnings of $2.72 per share on sales in the neighborhood of $120.3 million. Looking ahead, the company also set full-year guidance for 2018 comfortably ahead of the current Street views across the board.

Young man smiling over a few shipping containers, arrayed around his laptop.

Image source: Getty Images.

Now what

Stamps.com enjoyed a fantastic holiday season for online retailers. The company supports printing shipping labels for the USPS and 35 other shipping services, including several of the mailing solutions Amazon.com (NASDAQ:AMZN) runs on its own. So a good e-commerce season is great news for Stamps.com.

Moreover, the company is only dipping its toes into international waters so far. Modestly sized service launches in Canada, Australia, and the U.K. should serve as test markets for a worldwide expansion over the next few years. This way, Stamps.com's addressable market will grow from a $90 billion domestic opportunity to a $230 billion worldwide market.

It's not surprising to see Stamps.com shares soaring on these good tidings. The stock has now gained a market-beating 64% over the last year with a five-year return of 730%.

John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Anders Bylund owns shares of Amazon. The Motley Fool owns shares of and recommends Amazon and Stamps.com. The Motley Fool has a disclosure policy.