On Thursday, Gary Gensler, the chairman of the Securities and Exchange Commission (SEC) put Robinhood on notice and pledged to look into the operations of Citadel Securities. The new appointee of the Biden administrative, a protégé of Senator Elizabeth Warren, will be looking deeply at the “inherent conflicts” that appear in the payment-for-order flow business model. This is used by the Robinhood app and though the platform says it’s a zero commission brokerage app, there are hidden costs that need to be unraveled by the SEC.

Gensler addressed Congress’ concerns at the hearing on the investigation into GameStop, where a buying frenzy was created through a Reddit forum, WallStreetBets and the stock rode up and down, with a frenzy of buying and a temporary block in trading was imposed by the app.

The tough talker and hard worker had a lot of concerns about the Robinhood business model. Some of them include

• the cost which is inside the order execution
• the below the surface cost though the app touts itself as free, it’s not free but its zero commission
• the embedded game-like features which have since been removed

The Obama era regulator said that he would look into related aspects including the dominant position that Citadel Securities holds, as the Chicago based firm executes close to half of all retail trade volume at 47 percent and is the biggest revenue source for the app.

Gensler not only spoke of concentration but also mentioned his misgivings about the amount of data that is available to Citadel as a result of its superior position.

Billionaire Ken Griffin of Citadel Securities had earlier said that they play by the rules and they would change if the rules change. However, a Citadel spokesperson declined to comment when asked for a response by CNN Business.

Robinhood released a statement saying they would engage with the SEC and that they “intend to participate through the public notice and comment rulemaking process.”

Despite the congressional scrutiny after GameStop and the recent notice by the SEC, Robinhood is growing by leaps and bounds as its users increase, especially after the creation of its cryptocurrency division. It has filed to go public in March.

Market volatility is an old issue but new ways of trading especially fractional and cryptocurrencies trades and more have come to stay. No nonsense regulators like Gensler can advocate the much needed changes to balance the old and the new ways of trading.