To some extent. The movie takes cues from actual happenings in finance but adds fictional elements for dramatic effect. So, it's a blend of truth and creativity.
The movie Margin Call has elements drawn from actual occurrences in the financial world. However, it might have taken some creative liberties to make it more engaging for the audience.
Margin Call has elements of truth to it. It takes cues from the turmoil and decisions made in the finance industry around that time, but it's not a strictly factual account.
The margin call back story often begins with an investor's over - confidence or miscalculation. They might think the market will keep rising. But then, market conditions change, say due to economic news or industry - specific issues. For instance, in a tech - stock - heavy portfolio, if there is news of new regulations for tech companies, the stock prices could drop. And when that drop is significant enough to violate the margin agreement, the broker will call for more money. It's a story of risk and the consequences of leveraging investments.