Why was my order executed at a different price?

For a market order, this is expected: it’s designed to fill at the best available price at the moment of execution, which can differ from the last traded price you saw on screen, especially in a fast-moving or thinly traded stock. This gap is called slippage, and it tends to be larger when trading volume is low, when the bid-ask spread is wide, or during volatile periods like market open, close, or right after major news. For a limit order, the fill should never be worse than your specified price, though it can be better if the market gaps favourably. For a stop-loss order, once triggered it behaves like a market or limit order from that point, so the same slippage risk applies. You check the order type you used and the stock’s typical liquidity before assuming something went wrong; often it’s simply how that order type is designed to work.