Stocks have gone from rolling down a hill to falling off a cliff over the last three days. Below we highlight the worst performing stocks in the Russell 3,000 since Monday's close. In three days, 15% of stocks in the index are down more than 10%. That's a lot of value down the drain. While we are at extreme oversold levels and will probably get some gains in the next week or so, there has been a clear shift to a downtrend, and it's important to take profits if you play the upside and get some quick gains.