If a deposit intended to meet an IMD call occurs over the weekend or on a U.S. trading holiday, when will the deposit be applied?

Based on FINRA guidance, "as promptly as possible" with respect to an Intraday Margin Deficit (IMD) is defined as meeting the IMD call within three business days of when the IMD call was originally issued.

On the fourth instance of not satisfying an IMD within three business days over a 12-month rolling period, IBKR will consider the client to be making a practice of failing to satisfy an IMD "as promptly as possible."…

Yes, if there is a commodities cash requirement due to, for example, trading or a margin deficiency, funds will be moved from your securities account to satisfy the commodities requirement. As a result, funds deposited to meet your Intraday Margin Deficit (IMD) call may be transferred to your commodities account. The IMD call may remain outstanding due to the transfer…

If an account incurs an Intraday Margin Deficit (IMD) over a weekend or on a U.S. trading holiday, the deficit will be considered in the IMD call issued on the next business day…

The aging of an Intraday Margin Deficit (IMD) is calculated using the U.S. Trade Calendar, which defines business days based on U.S. market trading sessions and excludes weekends and market holidays…