Corporate Policy
IRS-defined window for substantiating expenses and returning excess advances.
Reasonable period is the IRS concept (Treasury Reg. 1.62-2(g)) defining the deadlines that keep a plan accountable: 60 days after the expense to substantiate; 120 days after the expense to return excess. The alternative "fixed-date" safe harbor accepts: advance paid no more than 30 days before, substantiation within 60 days, return within 120 days.