It's completely inaccurate to state that hedge funds didn't accelerate the downturn. As the value of their securities went down, and they were extremely leveraged, they had to meet their margin calls. At that point you can either raise money or sell assets. Nobody was investing so they sold assets. Selling assets then forced prices down further, causing other funds to need to liquidate, etc. This is called de-leveraging and it certainly has been very prevalent with hedge funds. Of course, this isn't JUST with hedge funds, but to say that hedge funds had nothing to do with this would be ignorant.