Kel08,
Holding a losing position in hopes that it will revert can work if the initial deviation was caused by an exogenous shock. Exogenous shocks are usually short term in nature.
However, for the market to deviate from its expected path for 4 months is long term. Some fundamental market dynamic has changed.
The way you described your situation, it was as if, you were running a black box where you were unaware of the logic of your indicators.
Once you start generating a series of losses, most would immediately investigate each loss to determine why actual was deviating from expected. This is related to
âI think I also asked this question of Lawrence Chan sometime back and he suggested that you could see the trading statistics deteriorate well before the system blew up but to be honest I didn't fully understand what he meant.â
Again - Without additional information on the market, time period traded, and system used, additional insight can not be provided.