The most interesting player in the GameStop story has gotten little attention: the DTCC, the centralized clearinghouse for stocks. It was the DTCC that raised the collateral requirements on memestocks and others, prompting Robinhood, Webull, etc. to put the buying ban in place.

If you want to complain about a lack of transparency on Wall Street, much better to focus on the DTCC than on Robinhood, since we don't know by how much it raised collateral requirements by or how it set that number.

The bigger point is that commission-free trading has created the illusion that investors can have infinite liquidity and instantaneous execution without any cost and without any risk. The bump in collateral requirements is a reminder that's not true, and that plumbing matters.