17 C.F.R. § 242.406 Undermargined accounts.
Title 17 - Commodity and Securities Exchanges
(a) Failure to satisfy margin call. If any margin call required by this Regulation (§§242.400 through 242.406) is not met in full, the security futures intermediary shall take the deduction required with respect to an undermargined account in computing its net capital under Commission or CFTC rules. (b) Accounts that liquidate to a deficit. If at any time there is a liquidating deficit in an account in which security futures are held, the security futures intermediary shall take steps to liquidate positions in the account promptly and in an orderly manner. (c) Liquidation of undermargined accounts not required. Notwithstanding Section 402(a) of this Regulation (§§242.400 through 242.406), section 220.4(d) of Regulation T (12 CFR 220.4(d)) respecting liquidation of positions in lieu of deposit shall not apply with respect to security futures carried in a securities account.
Title 17: Commodity and Securities Exchanges
PART 242—REGULATIONS M, SHO, ATS, AC, AND NMS AND CUSTOMER MARGIN REQUIREMENTS FOR SECURITY FUTURES
Customer Margin Requirements for Security Futures
§ 242.406 Undermargined accounts.