@new_trader Here is how limit orders work:A buy limit order will only get filled at or below the limit price. The limit is the maximum you are willing to pay. You put a 149.5 limit on it and got filled below your limit. That's good. A sell limit order will only get filled at or above the limit price. The limit is the minimum you are willing to receive. Your sell limit was way above the market so you did not get filled. A sell stop order is an order that gets activated once the stop price is reached. You always put sell stops below the current market price or they will be immediately activated. Once they are activated, they become market orders and will be executed at the current market price. You put a sell stop order way above the market so it was immediately active and it got filled. A sell stop limit order has two prices associated with it: the stop price is the price at which it becomes activated at which time it becomes a sell limit order at the limit price. And like any sell limit order, it is the minimum price you are will to receive. You did not use this order type. You used a sell stop order but not a sell stop limit order.
Hope that helps.