For the majority of quant equity hedge funds that have holding periods on the order of a few days to a couple weeks (“medium frequency” funds), by far the most common strategy is some variation of short-term mean reversion. Of course, while no hard data exists to support this claim, in my experience working alongside several dozen quant groups within two multi-strategy hedge funds, and admittedly
![Enhancing Short-Term Mean-Reversion Strategies](https://cdn-ak-scissors.b.st-hatena.com/image/square/3dbd9bdeebde1ac64e92e4d2998020a03923f754/height=288;version=1;width=512/https%3A%2F%2Fmedia.quantopian.com%2Fpublic%2Fog-image-default.png)