I received a message that NYSE issues R - Y could not trade due to a technical issue at the exchange. Consequently, all my 'market on open' orders at NYSE were cancelled except one. 'RATE' which had moved significantly against me did not cancel as opposed to e.g. 'RKUS,' which had generated a significant profit but was cancelled eliminating a significant profit. In other words: SELL RATE at the open: You execute an opening sell order at 9:56:28 (26.5 minutes after the opening) at 10.02 where the price is now 10.30. SELL RKUS at the open: You cancel the opening sell order of RKUS at 9:56:28 where the price is now 21.97 versus the opening price of 23.10. This is a surefire way to make a lot of money.