Note that I'm not saying that market maker profit is correlated to the performance of the wider stock market, just pointing out that market maker performance ca

Note that I'm not saying that market maker profit is correlated to the performance of the wider stock market, just pointing out that market maker performance can and will be affected by market-related factors that can cause all their market bets to go wrong at the same time, so the actual risk of losing money will always be much greater than what just naively applying the LLN says. Here's a couple of plausible factors: 1. A flash crash is just a huge coin flip -- even if your market making firm has circuit breakers that stop it from making more trades (and successfully kept its position small), if the exchange ends up ripping up trades en masse you may suddenly have a large position that loses you a lot of money 2. Someone screws up an algo [1] and you burn through more than your entire market cap in half an hour [1] https://www.bloomberg.com/news/articles/2012-08-02/knight-shows-how-to-lose-440-million-in-30-minutes https://www.bloomberg.com/news/articles/2012-08-02/knight-sh...