Startup costs are a few thousand a month. The firm I worked at has never had more than 3 people and was started by one nerd working out of his flat. You can spend a lot more if you want to do proper latency arb rather than price improvements, but bootstrapping your way to that point is hardly impossible.<p>I run algo strategies myself - not HFT - and my monthly trading costs are less than my monthly beer costs. Capital invested is perhaps 1-2 years savings for any software engineer (e.g., my best recent trade was dropping $40k on SPY when it was at $190, it&#x27;s now at $201.66).