Chairperson of Securities and Exchange Commission Gary Gensler said Wednesday that the regulator is eyeing tighter disclosure deadlines for hedge funds building sizable stakes in companies.

The agency is considering changing the rules under which hedge funds disclose that they have acquired 5% of a public company’s stock, Gensler said during a virtual Q&A at the Exchequer Club.

Schedule 13D filing takes 10 business days. Hedge funds have more than a week for secret purchases.

Gensler stated that “I would expect we’d have some on that,” adding that information asymmetry is a concern because people don’t know that there was a major player who bought up shares in the 10 day period.

Gensler explained that “Right now, once you cross the 5% threshold, you have 10 business days to file. That activist could in that time just move up from five – 6% to fifteen %, or vice versa, but that’s all they know is that there are nine days for the selling shareholders to be informed.”

In the 1960s, 13D was established to inform corporate managers about activities by activist shareholders or corporate raiders. In other words: Big investors can’t secretly acquire huge stakes to buy out a company to take it over without giving the company a chance of defense.

Criticiers of the rule claim that the deadline of 10 days is too short and that hedge fund managers will have more difficulty making a profit if their strategies are revealed to the public sooner than they should.

“It’s material nonpublic information that there’s an activist acquiring stock, who has an intent to influence and generally speaking, there’s a pop if you look at the economics from the day they announced … there’s usually a pop in the stock at least single-digit percent,” Gensler said. The selling shareholders at those times don’t know any of this material information.”