12 C.F.R. § 45.3 – Initial margin.

(a) Collection of margin. A covered swap entity shall collect initial margin with respect to any non-cleared swap or non-cleared security-based swap from a counterparty that is a financial end user with material swaps exposure or that is a swap entity in an amount that is no less than the greater of:
1. (1) Zero; or
2. (2) The initial margin collection amount for such non-cleared swap or non-cleared security-based swap less the initial margin threshold amount (not including any portion of the initial margin threshold amount already applied by the covered swap entity or its affiliates to other non-cleared swaps or non-cleared security-based swaps with the counterparty or its affiliates), as applicable.
(b) Posting of margin. A covered swap entity shall post initial margin with respect to any non-cleared swap or non-cleared security-based swap to a counterparty that is a financial end user with material swaps exposure. Such initial margin shall be in an amount at least as large as the covered swap entity would be required to collect under paragraph (a) of this section if it were in the place of the counterparty.
(c) Timing. A covered swap entity shall comply with the initial margin requirements described in paragraphs (a) and (b) of this section on each business day, for a period beginning on or before the business day following the day of execution and ending on the date the non-cleared swap or non-cleared security-based swap terminates or expires.
(d) Other counterparties. A covered swap entity is not required to collect or post initial margin with respect to any non-cleared swap or non-cleared security-based swap described in § 45.1(d). For any other non-cleared swap or non-cleared security-based swap between a covered swap entity and a counterparty that is neither a financial end user with a material swaps exposure nor a swap entity, the covered swap entity shall collect initial margin at such times and in such forms and such amounts (if any), that the covered swap entity determines appropriately addresses the credit risk posed by the counterparty and the risks of such non-cleared swap or non-cleared security-based swap.