The November $21 put options on Snapchat (SNAP) saw a massive 165-fold surge in volume, with over 30,200 contracts trading hands on Friday.
The bet, expiring in 60 days, is nearly 10 percent out-of-the-money, given the recent share price of $23.82 on Friday.
The trader buying the contracts paid about $1.25 per contract. For the option to profit at expiration, shares would need to slide under $20 between now and November.
Shares of the social media company are up nearly 40 percent in the past year. While revenue has been growing, the company is still operating at a loss. Shares have traded as high as $26.76 in the past few months, so any selloff would appear to be in the early stages.
That makes the November puts an ideal way for traders to bet on a further downside in shares in the coming weeks, and in a way that also makes for a solid market hedge.