Price touched but order didn't execute
In this short video Adrian Reid explains why a limit order can have its price level touched by the market yet remain unfilled. He describes how limit orders enter a queue behind all existing orders at the same price, so if there is a large volume of orders ahead, the market may not trade through enough shares to reach your order. Reid introduces the concept of a “touch fill,” where the price merely touches the limit level, and contrasts it with a true “penetration fill,” which requires the price to move through the limit price (e.g., from $10 to $9.99) to guarantee execution. He warns that assuming touch fills in backtesting leads to overly optimistic results for limit‑order strategies, and advises traders to design systems that only count fills after price penetration. The video ends with a call to like and subscribe for more systematic trading tips.
