Massachusetts’ top securities regulator has begun an investigation into trading platform Robinhood’s  decision to launch a prediction-markets hub that allows users to bet on the outcomes of a range of events, including March Madness college basketball tournaments.

Massachusetts Secretary of State Bill Galvin, in an interview with Reuters on Monday, said he was concerned that Robinhood was “linking a gambling event on a popular sports event that’s especially popular to young people to a brokerage account.”

“This is just another gimmick from a company that’s very good at gimmicks to lure investors away from sound investing,” said Galvin, a Democrat known as one of the country’s most aggressive state-level securities regulators.

His office sent Robinhood a subpoena last week seeking information related to how many of its brokerage account users in the state have requested to trade college sports events contracts as the men’s and women’s NCAA college basketball tournaments got under way, an official said.