This is the minimum amount of money we will 'Auto' transfer to you on any given night. If your earnings do not exceed this dollar amount then we'll roll them over into the next transfer that does reach the threshold.
Example: Say you set a minimum transfer amount of $20 and we only receive reported earnings of $18. That $18 would not go out on its own that night. Rather, it would be included in the next payment we send you which does exceed a total of $20.
This setting can be adjusted here.