Tech stocks are surging this year, but one trader is making a big bet that the hot streak may be over.

The Nasdaq 100 hit an all-time high this week as many of its top components continued to outperform the broader market. Apple, Microsoft, Amazon, Facebook and Alphabet — which account for roughly 40 percent of the index — are up 21, 4, 14, 22 and 10 percent, respectively, in 2017.

However, Mike Khouw of Optimize Advisors noted an increasing number of bearish bets in the space, particularly in the Nasdaq 100 ETF, the QQQ.

“One of the big bets that I saw [Wednesday] was a big purchase was of the [QQQ] April 129-strike puts for $1.10,” he said Wednesday on CNBC’s “Fast Money.” Khouw noted that 15,500 of those puts were purchased, meaning that this is a nearly $2 million bet that the QQQ will close below $127.90 by April expiration.

“What’s interesting about this bet to me is that these are going to expire on the 20th or thereabouts, which is actually before most of the big names in the QQQ [report] earnings. … This is somebody who is expecting a possible bearish downturn before then,” Khouw added.

The QQQ dipped slightly lower to $131.96 during Thursday’s trading session.