26 CFR 31.3406(b)(2)-5 - Reportable patronage dividend payment.
(a) Patronage dividends subject to backup withholding. A payment of a kind, and to a payee, that is required to be reported under section 6044 (relating to returns regarding patronage dividends) is a reportable payment for purposes of section 3406. See § 31.6051-4 for the requirement to furnish a statement to the payee if tax is withheld under section 3406.
(b) Amount subject to backup withholding - (1) Failure to provide taxpayer identification number or notification of incorrect taxpayer identification number. For purposes of sections 3406(a)(1) (A) and (B), the amount of a payment described in paragraph (a) of this section that is subject to withholding under section 3406 is the amount subject to reporting under section 6044, but only to the extent the payment is made in money. For purposes of this paragraph (b), money includes cash or a qualified check (as defined in section 1388(c)(4)).
(2) Notified payee underreporting or payee certification failure. For purposes of sections 3406(a)(1) (C) and (D), the amount of a payment described in paragraph (a) of this section that is subject to withholding under section 3406 is the amount subject to withholding under paragraph (b)(1) of this section, but only if 50 percent or more of that reportable amount is paid in money. Thus, a payor is required to withhold according to this paragraph (b)(2) on a payment if -
(i) There has been a notified payee underreporting described in section 3406(a)(1)(C) and § 31.3406(c)-1 or there has been a payee certification failure described in section 3406(a)(1)(D) and § 31.3406(d)-2;
(ii) The payor makes a reportable payment subject to reporting under section 6044 to the payee; and
(iii) Fifty percent or more of the payment is in cash or by qualified check.