> Trades get canceled/rejected because the price moves away from their limit/immediate-or-cancel order all the time
When your trade is occasionally beaten by someone at a different brokerage (or the same brokerage) that's normal. When there is a bot on the wire doing it every time that's a problem.
The changes in the price happen more often because they are marking up the price while the trade is still in progress. This doesn't help anybody except the HFT firm. Discovery isn't more efficient because the discovery has already happened, they set the price based on what they had discovered.
HFT profits are falling because people got wise to their system and built countermeasures.
When your trade is occasionally beaten by someone at a different brokerage (or the same brokerage) that's normal. When there is a bot on the wire doing it every time that's a problem.
The changes in the price happen more often because they are marking up the price while the trade is still in progress. This doesn't help anybody except the HFT firm. Discovery isn't more efficient because the discovery has already happened, they set the price based on what they had discovered.
HFT profits are falling because people got wise to their system and built countermeasures.