WATCH: Congressman Struggles to Understand Stock Trades During House GameStop Hearing, Melts Down as Witness Tries to Explain

Rep. Brad Sherman (D-CA) lashed out at Citadel CEO Kenneth Griffin at Thursday’s hearing of the House Financial Services Committee hearing, accusing him of trying to “evade” his question “by making up other questions” as Griffin attempted to tell the befuddled congressman how stock purchases are executed.

The exchange began with Sherman asking whether traders on the Robinhood trading platform received “as good a price” as those using Fidelity. Griffin’s firm bids against other market-makers, such as Virtu and UBS, to provide order flow — or fulfill stock purchases — for nine online exchanges, including TD Ameritrade, Charles Schwab, and the two Sherman cited.

That arrangement allows the platforms to offer fee-free trading, but led to controversy last month when the price of GameStop’s stock surged. Citadel lost 3 percent of its assets betting against the stock. Robinhood briefly prohibited users from purchasing the stock, even as users on other platforms were allowed to continue trading, allegedly because the company did not have enough capital to meet the regulatory requirements for volatile market conditions.

“Congressman, I believe that’s an excellent question,” Griffin replied to Sherman. “The execution quality that we can provide, as measured in terms of price improvement, is heavily related or correlated to the size of the order we receive…”

Sherman interrupted. “Don’t tell me there are other factors and take us down another road,” he said. “I’m asking you a clear question. Assuming same size of order, one comes in from Robinhood, one comes in from Fidelity, is it not true one is going to be getting an enhanced best execution, and the other one is just going to get best execution?”

Griffin attempted to answer once more. “So as I was trying to explain, because the Robinhood order comes from a community … of traders who tend to trade in smaller size…”

Sherman then erupted, gesticulating energetically. “That isn’t my question, sir! You’re evading my question by making up other questions!” he said, before repeating his question.

Griffin continued unperturbed. “The quality of the execution varies by the channel of the order,” he noted. “This is a commonly understood phenomena in economics, that channels matter. So for example, when you go get a mortgage, a mortgage from J.P. Morgan to their clientele has a different rate of interest than…”

Sherman again interjected. “Reclaiming my time, sir! Who gets the better deal? The one that comes from a broker being paid for order flow, and one not? Can you testify that, on balance, there’s no difference?” Griffin, attempting to reply, repeated his earlier observation that order size “is only one factor.”

“You are doing a great job of my wasting my time,” Sherman responded. “If you’re going to filibuster, you should run for the Senate.”

Watch above via the House Financial Services Committee.