Some night reading, I don't share this often. But just something for the peeps here to learn (probably won't get much traction cuz people are lazy most often). Your limit order is a static promise to trade at a fixed price. An informed trader, gets new information, will use a market order to execute against your stale price just before the entire market reprices. Ex: You have a limit order to buy a stock at $100.05. An informed trader learns of terrible news and knows the stock's true value is now $95. They will happily sell you all your shares at $100.05 right before the news becomes public and the price plummets. You're now fucked.