The venue can cut you off

Graduate · enrolled learners

This lesson opens with The Robinhood GameStop restriction, 28 January 2021.

What happened

At the height of the GameStop short squeeze, the brokerage Robinhood abruptly restricted its customers from buying GameStop and several other heavily-traded stocks, allowing them only to sell. The reason was not that Robinhood chose to take a side; it was that Robinhood's clearinghouse, the body that settles trades, demanded a very large increase in the collateral Robinhood had to post to cover the settlement risk of all that volume, a demand Robinhood could not immediately meet, so it cut off buying to reduce the risk it had to collateralize while it scrambled to raise billions in emergency capital. Customers who wanted to buy simply could not, through no fault of their own systems; the venue they depended on had cut off their access because the venue's own capital and clearing constraints were under stress. Nothing was hacked and no order was individually rejected for cause; a whole category of trades was switched off because the intermediary between the customer and the market could no longer afford the risk of letting them through.

The decision point

Access to a market through a venue is not a right the venue always honors; it is a service the venue can restrict or withdraw when its own systems, capital, or risk constraints are stressed, so a system that assumes it can always trade a venue it depends on is assuming a permanence the venue itself does not guarantee. The Robinhood restriction is the case: at the peak of a squeeze, customers were cut off from buying certain stocks, not for any fault of their own but because the broker's clearinghouse demanded collateral the broker could not immediately post, so the venue withdrew access to protect itself. This is a different failure from an outage or a rate limit: the venue is up and reachable, but it has decided, or been forced, to stop letting you do something, and your ability to trade is gone even though nothing on your side broke. The deeper point is that between a trader and the market sits an intermediary with its own solvency, risk limits, and regulators, and that intermediary's constraints can override the trader's intentions, cutting off access exactly during the extreme conditions that stress the intermediary. So the discipline is to recognize that trading a venue depends on the venue's willingness and ability to let you, which can vanish under stress, to avoid strategies that assume uninterrupted access to a single venue, especially in the extreme moves when a venue is most likely to restrict, and to have a plan for being cut off that does not rely on the venue that just cut you off. The Robinhood restriction is what it looks like when the intermediary, not the market, decides you cannot trade, and its lesson is that access is contingent on the venue's own condition, not guaranteed by your intent.

Orientation and Year One are open: anyone can read them without an account. From Year Two onward the lessons are for enrolled learners, because progress through the later years only means anything if it is tracked against a record.

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