Order execution discussion

Order routing and execution quality affect your realized price. Limit orders give you control; market orders give you speed. For illiquid stocks, always use limit orders to avoid wide fills.

Slippage — the difference between your expected fill and actual fill — is highest at market open, during news events, and in thinly traded securities. Account for it when back-testing strategies.

If you receive an unexpected fill price, review the Time & Sales for that symbol at that moment. Most 'bad fills' are explainable by a wide spread or a momentary price spike.