11 U.S.C. § 553: Setoff

the claim of such creditor against the debtor is disallowed; after the commencement of the case; or after 90 days before the date of the filing of the petition; and while the debtor was insolvent (except for a setoff of a kind described in section 362(b)(6), 362(b)(7), 362(b)(17), 362(b)(27), 555, 556, 559, 560, or 561); or after 90 days before the date of the filing of the petition; while the debtor was insolvent; and for the purpose of obtaining a right of setoff against the debtor (except for a setoff of a kind described in section 362(b)(6), 362(b)(7), 362(b)(17), 362(b)(27), 555, 556, 559, 560, or 561). 90 days before the date of the filing of the petition; and the first date during the 90 days immediately preceding the date of the filing of the petition on which there is an insufficiency. In this subsection, “insufficiency” means amount, if any, by which a claim against the debtor exceeds a mutual debt owing to the debtor by the holder of such claim. For the purposes of this section, the debtor is presumed to have been insolvent on and during the 90 days immediately preceding the date of the filing of the petition.