I don't endorse this site directly, but they seem to have a good article on firms and their differences: https://www.thewallstreetquants.com/cone1-firm-list
- Citadel: Very intense work culture, but there are good methodologies to be learned here about trading.
- Two Sigma: Very tech-friendly these days given how many SWEs they have. Almost like "big-tech" but in trading.
- Optiver: Options house
- SIG Susquehanna: Big options house
- Akuna
- Virtu
- Chicago Trading Company
- Jump Trading
- Jane Street: A top-tier quant firm
- HRT: Well-known for their high-frequency trading
- PDT Partners
- Renaissance Technologies
- Headlands: Academic-driven, very high quality software
- Old Mission Capital
- Vatic Investments: Top-tier firm well-known for their ML research in trading
- Tower
- DRW
Some of the firms above are market makers as well. But putting some here to have some sort of separation.
- Citadel Securities: Yes, Citadel and Securities are different. Citadel Securities is primarily a market-maker.
- Wincent: Crypto market-making firm
If you work in software, you will often be approached by headhunters who work in companies that try to earn money from successful referrals of candidates. Their "talent search" is pretty much just picking people from FANG and then forcing them down a few pipelines for Quant or SWE in Trading. There are often unethical practices here where they try to tell you as many questions as they can, based off of previous candidates' experience. You can argue that even knowing the answer doesn't really guarantee you the job, since you might be asked throw-up questions or unexpected surprises that you can't prepare for, e.g. your working style or thinking process. I think in general, it's not a terrible way to apply to firms, but it is a bit annoying knowing that someone is getting paid a lot for your referral (and they will bother you a lot if you end up getting an offer. They want that check).