17 C.F.R. § 300.501
(a) Where a SIPC member (“Debtor”) held securities in an account for a customer, the customer has a “claim for cash” with respect to any authorized securities sale:
(b) Where the Debtor held cash in an account for a customer, the customer has a “claim for cash”, notwithstanding the fact that the customer has ordered securities purchased for the account, unless: