What happened

Shares of SINA Corp. (NASDAQ:SINA) were down 10.2% as of 3:30 p.m. EDT Wednesday despite strong first-quarter 2018 results from the Chinese internet media company.

More specifically, SINA's net revenue climbed 59% year over year to $440.8 million, which translated to adjusted (non-GAAP) net income of $35.2 million, or $0.47 per share. Both the top and bottom lines arrived ahead of investors' expectations for earnings of $0.42 per share on revenue of $433.3 million.

SINA company logo in red and black

IMAGE SOURCE: SINA.

So what

SINA Chairman and CEO Charles Chao called it a "good start" to the year, noting that the company enjoyed "robust" revenue growth and improved monetization from Weibo, in which it owns a majority stake, and continued progress with mobile monetization from its portal business.

To be sure, SINA's advertising revenue soared 61% year over year this quarter to $440.8 million, driven by a 79% increase in Weibo ad and marketing sales. And non-advertising revenue jumped 47% to $73.7 million, led by a combination of Weibo gaming and membership services, as well as sales from SINA's budding fin-tech business.

Now what

It's unclear, then, exactly why SINA is falling today -- though that's not entirely out of character for the stock. In fact, you might recall that SINA shareholders endured similar post-earnings plunges in spite of strong quarterly results multiple times en route to the stock's 65% gain for all of 2017. And for perspective, SINA was already up more than 35% over the past year as of yesterday's close.

So while today's market reaction might not indicate as much, these results were undeniably impressive. And I think long-term SINA shareholders have no reason to be worried.

Steve Symington has no position in any of the stocks mentioned. The Motley Fool recommends Sina. The Motley Fool has a disclosure policy.