Losing streaks and the daily rules

At a 45% win rate, over one hundred trades, the probability of stringing together five losses at least once exceeds 85%. Six losses in a row happen about two times out of three. These are not accidents: they are the normal variance of a real edge. The account has to get through them without changing anything in the method, and the daily and weekly rules exist for that, not to cap the gains.

Why −2R and not −4R

The daily limit is 4R. Why stop at −2R? Because the last two R of a losing day are almost always taken on catch-up setups, graded AA out of complacency. And because a prop firm account has an intraday limit: if you reach −2R at 6 pm, you still have a margin for a slippage, an outage, a misclick.