A customer fails to make a timely payment for a substantial purchase in a cash...

Under Federal Reserve Regulation T, if a customer does not pay for a purchase in a cash account within the required payment period and the firm does not grant an extension, the firm must liquidate the securities (sell them) and impose a 90-day freeze on the account’s ability to purchase securities on credit, which corresponds to choice B. The “freeze” means that for 90 days the customer must make full payment in advance (or deliver fully paid funds) before new purchases can be made in that account. This is a classic SIE test area tied to cash account payment rules and settlement discipline.

Choice A is incorrect because the rule does not require the firm to close the account; the standard remedy is liquidation and restriction (freeze). Choice C is incorrect because merely warning the customer does not satisfy the regulatory requirement; the firm must take action to address the unpaid trade. Choice D is incorrect because firms cannot simply convert the transaction into a margin obligation to avoid Regulation T cash account rules. Establishing a margin account requires proper account documentation and suitability/approval, and it does not retroactively “cure” a cash account payment violation.

The compliance purpose behind this rule is to prevent “free riding” behavior—customers attempting to buy securities and then selling them before paying, using sale proceeds to cover the purchase without providing funds. Regulation T supports orderly markets by requiring timely payment and imposing restrictions when customers fail to meet obligations. For exam purposes, remember the key pairing: failure to pay → liquidation + 90-day freeze (unless an extension is granted).