IHS Markit forecasts short interest in Facebook to have totaled 29.2 million shares on Friday, up from 25.9 million in mid-March. That's still a small amount relative to the shares available for trading on the social media stock, but it indicates that some hedge funds could be looking to capitalize on any stumbles as Zuckerberg looks to repair the company's reputation.
Facebook shares have tanked more than 13 percent in the past month after it was reported that political research firm Cambridge Analytica was able to gather personal information from millions of Facebook users without their consent.
The decline in Facebook's stock also pressured the broader tech sector, which is down nearly 7 percent over the past month.
Zuckerberg is scheduled to testify in front of the Senate Judiciary and Commerce committees in a joint hearing Tuesday. Facebook's stock rose 1.6 percent ahead of the hearing.
— CNBC's Evelyn Cheng contributed to this report.