Direct Deposit. The banks can see the incoming transaction before the amounts clear. Payroll often starts the process two days early anyways since they try and get it to land on the 1st and 15th or whatever the dates are, so when the bank sees the incoming transaction it'll just automatically give me the funds while the clearing happens in the background.

Its honestly the same kind of logic they're using when you deposit your paycheck and it seems to clear turbo fast.