We discussed the possibility of and the impact of other market participants discovering our trading signals and using the same signals that our trading strategies utilize to make money. Similar to other market participants discovering the same trading signals that our trading strategies use and hurting our profitability, it is possible for other market participants to discover our order flow and strategy behavior and then find ways to anticipate and leverage our trading strategy's order flow to trade against us in a way that causes our trading strategies to lose money.

Other ways other market participants can discover our order flow and anticipate market price moves in different asset classes or other trading instruments, perhaps for stat arb or pair-trading strategies or cross-asset strategies. This can lead to reduced profitability or it can worsen to a point where it is no longer feasible to continue running the specific algorithmic trading strategy. Sophisticated market participants often invest a lot of thought, design, and resources to make sure that the algorithmic trading strategy behavior does not immediately give away the strategy's behavior in a way that can be used by other market participants to hurt our trading profitability.

This often involves the use of GTC orders to build queue priority in FIFO markets, using icebergs to disguise the true liquidity behind orders, using stop orders to be triggered at specific prices ahead of time, using Fill and Kill or Immediate or Cancel orders to mask the true liquidity behind orders being sent to the exchange, and complicated order-execution strategies to hide the trading strategy's true intention. Obviously, trying to hide intentions from other market participants can be taken too far, as we saw in the case of Spoofing, which is an illegal algorithmic trading practice. In summary, to use sophisticated trading strategies in a very competitive and crowded market, the strategy implementation can often be a lot more complex than it needs to be for the purposes of mitigating information leak and reduced profitability.