How Buying Power is Calculated

Your buying power information is updated at the following times:

Account Information	Update Time
Beginning Day Trading Buying Power	Updated after hours. Does not change during the trading day.
Beginning Overnight Buying Power	Updated after hours. Does not change during the trading day.
Remaining Day Trading Buying Power	Updated as positions are opened and closed.
Remaining Overnight Buying Power	Updated as positions are opened and closed.
Realized Profit & Loss Day	Updated as positions are closed.

Calculations

The amount your buying power is adjusted depends on the type of:

account (margin or cash)
security (marginable or non-marginable)
transaction (opening, closing a day trading position, or closing an overnight position)

The buying power adjustment is calculated as follows:

Abbreviations used in calculations:

TA = Transaction Amount
IR% = Initial Requirement Percent
NA = Not Applicable
OBPA = Original Buying Power Adjustment (amount adjusted for the opening transaction)

Margin Accounts

Opening Transactions
Buying Power Type	Marginable Security		Non-Marginable Security
Buying Power Type	Sell Short	Buy	Sell Short	Buy
Day Trading BP	TA * IR% * 4	TA * IR% * 4	NA	TA * 4
Overnight BP	TA * IR% * 4	TA * IR% * 4	NA	TA * 2

Closing Overnight Positions
Buying Power Type	Marginable Security		Non-Marginable Security
Buying Power Type	Sell	Buy to Cover	Sell	Buy to Cover
Day Trading BP	No Change	No Change	No Change	NA
Overnight BP	TA	TA	TA * 2	NA

Closing Day Trading Positions
Buying Power Type	Marginable Security		Non-Marginable Security
Buying Power Type	Sell	Buy to Cover	Sell	Buy to Cover
Day Trading BP	OBPA	OBPA	OBPA	NA
Overnight BP	OBPA	OBPA	OBPA	NA

Cash Accounts

Opening Transactions
Buying Power Type	Marginable Security		Non-Marginable Security
Buying Power Type	Sell Short	Buy	Sell Short	Buy
Day Trading BP	NA	TA	NA	TA
Overnight BP	NA	TA	NA	TA

Closing Overnight Positions
Buying Power Type	Marginable Security		Non-Marginable Security
Buying Power Type	Sell	Buy to Cover	Sell	Buy to Cover
Day Trading BP	TA	NA	TA	NA
Overnight BP	TA	NA	TA	NA

Closing Day Trading Positions
Buying Power Type	Marginable Security		Non-Marginable Security
Buying Power Type	Sell	Buy to Cover	Sell	Buy to Cover
Day Trading BP	No Change	NA	No Change	NA
Overnight BP	No Change	NA	No Change	NA