An IB Reg T Margin account allows borrowing to support:
Margin requirements are computed on a formula-based real-time basis, with immediate position liquidation if the minimum maintenance margin requirement is not met. Purchase and sale proceeds are immediately recognized. US securities regulations require at least USD 25,000 (or USD equivalent) in equity to day trade.
For buying options, you must deposit the entire premium plus commissions. For selling options and other strategy-based combinations, the margin requirements and commissions must be covered. Option market value may never be used for the purpose of borrowing funds. You must have stocks margin trading permissions in order to have options margin trading permissions.
Please note that for commodities, "margin" refers to the amount of cash that must be put up BY THE CLIENT as collateral to support a transaction, in contrast to margin for securities which refers to the amount of cash a client borrows from IB. For futures trading, special 50% of variation margin benefits are made available during the day on some futures exchanges.
Borrowing in one currency to purchase another currency is allowed, but margin haircuts will be applied on a real-time basis. Margin accounts automatically get Forex trading permissions in order to effect trading of products denominated in multiple currencies.
Borrowing to support bond trading. Margin requirements are computed on a real-time basis, with immediate position liquidation if the minimum maintenance margin is not met. Purchase and sale proceeds are immediately recognized. Shorting of bonds is not allowed.
Borrowing to support Mutual Funds may only be done 30 days after the purchase of the fund. Shorting Mutual Funds is never allowed. Net Asset Value is computed once per day at closing by the funds at which time your margin requirement and equity will be updated. Liquidation will occur on an end-of-day basis if minimums aren't met. Purchase and sales proceeds are recognized at the end of the day when the Mutual Fund order is submitted and confirmation received.
This also includes the purchase and sale of stocks, exchange traded funds and narrow based index futures contracts on margin. Margin is determined on a real-time basis with immediate position liquidation if the minimum margin requirement is not met. In the US, SSFs may be cross margined with stocks and options (IRA accounts can only cross margin SSFs, not stocks and options).
To compare the characteristics of a Reg T margin account with those of Cash and Portfolio Margin accounts, see the Account Types comparison table.