DE Shaw takes directional risk. They have a lot of conventional strategies iirc (distressed debt, credit, etc.). Jane Street does a lot of ETF AP and other strategies that optimize for technology (afaik).
Alameda is/was strategies that optimize for technology, arbitrage etc. But with a massive one way directional long bet over the top.
Run by people with 1-2 years experience in shops that run a market neutral profile , in an environment where they believed the underlying asset goes up every single day.
