Introduction
As a global broker offering futures trading in 19 countries, IB is subject to various regulations, some of which retain the concept of margin as a single, end of day computation as opposed to the continuous, real-time computations IB performs. To satisfy commodity regulatory requirements and manage economic exposure in a pragmatic fashion, two margin computations are performed at the market close, both which must be met to remain fully margin compliant. An overview of these computations is outlined below.

Overview
All orders are subject to an initial margin check prior to execution and continuous maintenance margin checks thereafter. As certain products may be offered intraday margin at rates less than the exchange minimum and to ensure end of day margin compliance overall, IB will generally liquidate positions prior to the close rather than issue a margin call. If, however, an account remains non-compliant at the close, our practice is to issue a margin call, restrict the account to margin reducing transactions and liquidate positions by the close of the 3rd business day if the initial requirement has not then been satisfied.

In determining whether a margin call is required, IB performs both a real-time and regulatory computation, which in certain circumstances, can generate different results:

Real-Time: under this method, initial margin is computed using positions and prices collected at a common point in time, regardless of a product’s listing exchange and official closing time; an approach we believe appropriate given the near continuous trading offered by most exchanges.

Regulatory: under this method, initial margin is computed using positions and prices collected at the official close of regular trading hours for each individual exchange. So, for example, a client trading futures listed on each of the Hong Kong, EUREX and CME exchanges would have a requirement calculated based upon information collected at the close of each respective exchange.
 

Impact
Clients trading futures listed within a single country and session are not expected to be impacted. Clients trading both the daytime and after hours sessions of a given exchange or on exchanges located in different countries where the closing times don’t align are more likely to be impacted. For example, a client opening a futures contract during the Hong Kong daytime session and closing it during U.S. hours, would have only the opening position considered for purposes of determining the margin requirement. This implies a different margin requirement and a possible margin call under the revised computation that may not have existed under the current.  An example of this is provided in the chart below.
 

Example

This example attempts to demonstrate how a client trading futures in both the Asia and U.S. timezones would be impacted were that client to trade in an extended hours trading session (i.e., outside of the regular trading hours after which the day's official close had been determined).  Here, the client opens a position during the Hong Kong regular hours trading session, closes it during the extended hours session, thereby freeing up equity to open a position in the U.S. regular hours session. For purposes of illustration, a $1,000 trading loss is assumed. This example illustrates that the regulatory end of day computation may not recognize margin reducing trades conducted after the official close, thereby generating an initial margin call.