First, we need to understand what factors cause trading strategies that were initially profitable to slowly decay in profitability and eventually no longer be profitable at all. Having a good understanding of what possible factors can cause a currently profitable algorithmic trading business to deteriorate over time can help us put checks and re-evaluation mechanisms in place to detect these conditions and deal with them in time in order to maintain profitability of the algorithmic trading business. Now let's look at some of the factors involved in profit decay for algorithmic trading strategies.