Shares of Snap fell below their IPO price on Monday, just ahead of a crucial period for the social media stock.

Snap shares dipped to a low of $16.95, closing at $16.99, just below the $17 price of the March public offering.

The IPO was 12 times oversubscribed at the time, sources told CNBC. But since then, shares have tumbled from their March 3 high of $29.44.

Source: FactSet

Snap, which makes ephemeral messaging app Snapchat, is about to see the end of its lock-up period. When that period hits at the end of the month, insiders can begin selling their shares.

Facebook, Twitter and LinkedIn fell an average of 24 percent in the 30 days ahead of their lockup expirations, according to MKM Partners. Snap shares have fallen nearly 19 percent in the past three months, and about 6 percent over the past month.

— CNBC’s Evelyn Cheng contributed to this report.