that question is a little trickey to understand...
are you asking how much money we leave in our nochex accounts? I normally leave about £5.00 in there just inase i see somthing good and cheap on ebay that i like hehe. saves me getting money out of acocunt hehe.
Normally, for processors, the period is 180 days.
It really depends on how much sales you have on an average weekly basis and how much you have in the Rolling Reserve.
If your sales stop, the processing company will normally have to hold onto the money for 180 days, at least hold the Rolling Reserve as they have a 180 day liability period for credits and chargebacks for every order on your account.