I trade direct access but my IRA is with an online broker. According to my broker, market makers have 30 seconds to fill an order even if it trades through the price. At 14:21 today I entered an order to buy NVDA at 27.18 At 14:26 the price trades through 27.18 down to 27.10 Over 50K shares traded that minute - no fill. At 14:27 the price heads back up I call the broker to complain, they call the mm (NITE), and the answer I get is it didn't trade below the price for more than 30 seconds so they're not obligated to fill me. If this is true, then every mm can hold any order for 30 seconds as it drops below your price, buy it at the lower price and pocket the spread. If it trades above, they just claim "30 sec rule". No risk. They must have some really sh!tty traders to be losing money with these advantages. I wish I had 30 seconds to back out of or change the price on every trade I get into.