I have a Reg-T margin account with Interactive Brokers. I would like to confirm my assumptions about the effect that making a cash withdrawal on margin would have on the account.

Let's say I have $200 worth of securities in the account; all of it paid for with my own cash (no margin balance), and cash balance of $0. Under these parameters, IB shows:

  • Maintenance margin of $50
  • Buying power of $600
  • Excess liquidity of $150

Let's say I withdrew $100 in cash from the account. Because my previous cash balance was $0, that effectively means that the whole $100 is being borrowed on margin. How would that affect the numbers above?

Ultimately, what I'm trying to figure out is by how much the $200 in securities in the account would have to come down in value before triggering a margin call because of the $100 loan.

1 Answer 1


You can disregard the Buying Power number because that relates to the 4X intraday margin that a Pattern Day Trader is allowed. The PDT requirement is $25k account value and this is only a $200 account.

What you are suggesting amounts to buying $200 worth of stock with $100.

The account value level at which a margin call will be triggered is:

Account Value = (Margin Loan) / (1 – Maintenance Margin %)

If the maintenance level is 25% then the Maintenance Requirement is 4/3 x the Debit Balance. In your example, 4/3 of $100 would be $133.33. This level would be reached after you lost 1/3 of your position's value (1/3 x $200). The numbers would look like this:

 Market Value   Loan   Equity   Margin %
    200.00     100.00  100.00    50%    (initial position)
    133.33     100.00   33.33    25%    (after 1/3 drop)

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.