Snapchat's stock dropped as much as 5 percent to a new low as its IPO "lockup" period expired Monday, allowing early insiders and employees to sell up to 400 million shares.

Though Snap shares briefly recovered and traded positively midday Monday, investors turned pessimistic throughout the afternoon as this long-anticipated negative catalyst may mark a bottom. The shares traded as high as $13.98, representing a gain of 17 cents.

After the closing bell, the stock sat down 14 cents at $13.67, down 1.01 percent.

The stock first fell below its $17 IPO price in July and has been under tremendous pressure into this lockup expiration, down 22 percent in one month heading into Monday.

Since its initial public offering on March 2, insiders including CEO Evan Spiegel have been barred from selling Snap shares, even as the social media company struggles on Wall Street. However, early investors and insiders including Spiegel, CTO Robert Murphy and Lightspeed Ventures will be able to sell up to 400 million shares starting Monday, according to a report by JPMorgan analyst Doug Anmuth. Other employees will be able to sell up to an additional 782 million shares on Aug. 14. About 97 percent of Snap stock will be available for trading by the end of August, Anmuth said.

But the insider selling that may come this month may already be priced into the stock, history shows.

MKM derivatives strategist Jim Strugger noted that many of the now-successful social media companies tracked a similar pattern around their lockup expiration. According to Strugger, over the month preceding Facebook, Twitter and LinkedIn's "lockup" expiration, their stocks were down by an average of 24 percent, about the same as Snap's decline.

Past social network stocks around lockup

Source: MKM Research

"Notably, LinkedIn, Twitter and Facebook all bottomed within a week of their lockup expirations, a bias that points to getting directionally long SNAP down here," noted Strugger.

The social media company disappointed analysts after its first earnings report in May, largely because many of its features are being imitated by rival Facebook. It added just 8 million users during that quarter, far below the 59 million added by Facebook globally over the same period. Snap is scheduled to report its next quarterly earnings on Aug. 10.

"Often you can see these lockup expirations be more of a bottoming event for stocks rather than a negative event," Michael Graham of Canaccord Genuity told CNBC's "Squawk Alley" on Monday. "There's a lot of negative sentiment going into an event like this and in this case it will stretch out for several weeks. It does take some time, usually, for the shares to get into the market. I think the more important thing for Snap is to show some execution when they report next Thursday."

Disclosure: CNBC parent NBCUniversal is an investor in Snap.

— With reporting by CNBC's Anita Balakrishnan and Michelle Castillo.