something doesn't sound right. if a corporation made the loan, (the shareholders own the corporation) then it's the corporation that should have taken the write-off not the shareholders directly. If it resulted in the worthlessness of the corporation that made the loan. then the shareholders would take a deduction for a worthless security, not a bad debt.
my answer would be different if the shareholders personally loaned the money.
anyway, the recovery is taxable and reported on the same form where the loss was recorded