Offer your thoughts or opinion on the input financial query or topic using your financial background.

Setting a trailing stop loss at $39.70 bid price, stock sold at $41
There could be a number of reasons: The price hit your number ($39.70) but by the time your order hit the market, the price had gone up. Perhaps the stock went up between when you placed the stop loss and when the order was executed. A trailing stop loss will ratchet up: Very simply, the trailing stop maintains a stop-loss order at a precise percentage below the market price (or above, in the case of a short position). The stop-loss order is adjusted continually based on fluctuations in the market price, always maintaining the same percentage below (or above) the market price.