High Frequency Order Flow Decay

High frequency order flow decay describes the rapid loss of predictive power in short-term market data as a trading signal is exploited. In electronic trading, as soon as a profitable pattern or inefficiency is identified, competing algorithms react to it, causing the opportunity to vanish.

This decay happens in milliseconds, meaning that the alpha generated by a specific order flow signal diminishes as more participants observe the same data. Scalpers must constantly refine their models to account for this decay, often rotating through different signals to stay ahead of the market.

It highlights the competitive nature of algorithmic trading where speed and adaptability are the primary drivers of performance. Understanding decay is vital for managing the lifespan of a trading strategy.