If the S&P 500 drops below 2,100 by the end of next year, one Wall Street punter will face a costly — and now, high-profile — reckoning.

According to Trade Alert data cited by Reuters, an anonymous trader made waves in the options market on Monday by selling 19,000 put options on the S&P 500 SPX, -1.11% , which obligates him or her to buy the market benchmark if it drops 22% by December 18, 2020.