Overview of the SPAN margining system

The Standard Portfolio Analysis of Risk (SPAN) is a methodology developed by the CME and used by many clearinghouses and exchanges around the world to calculate the Performance Bond (i.e., margin requirement) on futures and options on futures which the clearinghouse collects from the carrying FCM and the FCM, in turn, from the client.

SPAN establishes margin by determining what the potential worst-case loss a portfolio will sustain over a given time frame (typically set to one day), using a set of 16 hypothetical market scenarios which reflect changes to the underlying price of the future or option contract and, in the case of options, time decay and a change in implied volatility. 

The first step in calculating the SPAN requirement is to organize all positions which share the same ultimate underlying into grouping referred to as a Combined Commodity group. Next, SPAN calculates and aggregates, by like scenario, the risk of each position within a Combined Commodity, with that scenario generating the maximum theoretical loss being the Scan Risk. The 16 scenarios are determined based upon that Combined Commodity’s Price Scan Range (the maximum underlying price movement likely to occur for the given timeframe) and Volatility Scan Range (the maximum implied volatility change likely to occur for options).

Assume a hypothetical portfolio having one long future and a one long put on stock index ABC having an underlying price of $1,000, a multiplier of 100 and a Price Scan Range of 6%.  For this given portfolio, the Scan Risk would be $1,125 scenario 14.





1 Long Future

1 Long Put


Scenario Description





Price unchanged; Volatility up the Scan Range





Price unchanged; Volatility down the Scan Range





Price up 1/3 Price Scan Range; Volatility up the Scan Range





Price up 1/3 Price Scan Range; Volatility down the Scan Range





Price down 1/3 Price Scan Range; Volatility up the Scan Range





Price down 1/3 Price Scan Range; Volatility down the Scan Range





Price up 2/3 Price Scan Range; Volatility up the Scan Range





Price up 2/3 Price Scan Range; Volatility down the Scan Range





Price down 2/3 Price Scan Range; Volatility up the Scan Range





Price down 2/3 Price Scan Range; Volatility down the Scan Range





Price up 3/3 Price Scan Range; Volatility up the Scan Range





Price up 3/3 Price Scan Range; Volatility down the Scan Range





Price down 3/3 Price Scan Range; Volatility up the Scan Range





Price down 3/3 Price Scan Range; Volatility down the Scan Range





Price up extreme (3 times the Price Scan Range) * 32%





Price down extreme (3 times the Price Scan Range) * 32%

The Scan Risk charge is then added to any Intra-Commodity Spread Charges (an amount that accounts for the basis risk of futures calendar spreads) and Spot Charges (A charge that covers the increased risk of positions in deliverable instruments near expiration) and is reduced by any offset from an Inter-Commodity Spread Credit (a margin credit for offsetting positions between correlated products).  This sum is then compared to the Short Option Minimum Requirement (ensures that a minimum margin is collected for portfolios containing deep-out-of-the-money options) with the greater of the two being the risk of the Combined Commodity. These calculations are performed for all Combined Commodities with the Total Margin Requirement for a portfolio equal to the sum of the risk of all Combined Commodities less any credit for risk offsets provided between the different Combined Commodities. 

The software for computing SPAN margin requirements, known as PC-SPAN is made available by the CME via its website.

Are the funds I deposited today considered for buying power calculations?


The answer is yes.  To calculate buying power IB compares Current Equity with Loan Value to Previous Day Equity with Loan Value.  Whichever figure is lesser is used.  From the lesser of these two figures, the Initial Margin Requirement on the positions you currently hold in the account is subtracted.  The difference is then multiplied by the current leverage amount (at present 4:1), which results in your intraday buying power.  Funds deposited today are now considered as part of Previous Day ELV. 

Please understand that funds deposited today will not be considered until they have cleared all appropriate funds and banking channels and are officially in the account. 

Also note that this calculation of buying power applies to Regulation T margin type accounts and not to Portfolio Margin type accounts. 

The Previous Day ELV check is done once an account is labeled as a "Pattern Day Trader" account.  This occurs when the account has completed 4 day trades in a 5 day period.  If the account is not labeled as a PDT, then the Previous Day ELV check doesn't apply. 


The equation used is:


((Lesser of: Equity With Loan Value or Previous Day Equity With Loan Value) - Initial Margin)*4 for accounts labeled as PDT accounts.

(Equity With Loan Value - Initial Margin)*4 for accounts not labeled as PDT accounts.

Does IBKR provide for a dormant or inactive account status?

As the IBKR business model, by design, is oriented towards active traders, there is no provision for dormant or inactive account status. As long as an account remains funded it will be subject to the monthly minimum activity fee of USD 10 if the account balance is above USD 2,000 (or equivalent) and USD 20 once the account balance falls below USD 2,000 (this minimum activity fee is set at USD 3 for account holders age 25 and under). Also, should the account balance fall below USD 2,000 IBKR is precluded, by regulation, from affording margin treatment to securities positions. In addition, account holders will also be billed for any market data subscriptions maintained and, as a matter of policy, will have subscriptions terminated automatically when the account balance falls below USD 500.

Also note that the monthly minimum activity fee will continue to be assessed until such time the account no longer has equity, at which point it will be automatically closed. Should funds be transferred back into the account, thereby reopening the account, the monthly activity fee will once again be assessed.

Individuals seeking to close an account are encouraged to refer to our User's Guide to familiarize themselves with the steps and prerequisites for taking this action.

Will IBKR delay liquidation while I deposit funds in my account?


IBKR's margin compliance policy does not allow for transfers or other deposits if there is a margin violation/deficit in the account.  In the case of a margin violation/deficit, the account in deficit is immediately subject to liquidation. Automated liquidations are accomplished with market orders, and any/all positions in the account can be liquidated. There are cases where, due to specific market conditions, a deficit is better addressed via a manual liquidation.

Funds deposited or wired into the account are not taken into consideration from a risk standpoint until those funds have cleared all the appropriate funds and banking channels and are officially in the account. The liquidation system is automated and programmed to act immediately if there is a margin violation/deficit.

Note for Prime Clients: Executing away is not a means to resolve real time deficits as away trades will not be taken into consideration for beneficial margin purposes until 9 pm ET on Trade Date or when the trades have been reported and matched with external confirms, whichever is later. Trading away for expiring options, on expiration day, is also discouraged due to the potential for late or inaccurate reporting which can lead to erroneous margin calculations or incorrect exercise and assignment activity. Clients who wish to trade expiring options on expiration day and away from IB, must load their FTP file no later than 2:50 pm ET, and do so at their own risk.

What is Interactive Broker's margin rules for stocks below $5?


Interactive Brokers does not have a special rule regarding stocks that trade below $5. Although other brokerage firms may have a house rule regarding stocks trading below $5, IBKR does not employ such a rule.


There are other IBKR-specific rules to consider in this scenario.  In general, IBKR would not have a special rule for long positions in stock trading below $5, as long as they are exchange-listed. Once a stock is delisted from one of the exchanges and moved to the OTC market, it would be subject to a 100% margin requirement, since the stock would no longer be considered marginable. 

Also, for long positions, the maintenance margin requirement is 30% of the stock value or $2,000, whichever is greater.

For short positions, the maintenance requirement on stock greater than $5, is $5 per share or 30% of the stock value, whichever is greater.  For short positions in stock where the last sale price/share is less than $5, then the maintenance margin requirement is $2.50 per share or 100% of the stock value, whichever is greater.

How do I upgrade my cash account to a margin account?


Requests to have an account upgraded from a 'Cash' type to 'Margin' type can be initiated by logging in to Client Portal and selecting the Settings and Account Settings sections and clicking the gear icon next to the words "Account Type" in the Configuration section. IBKR offers two margin types: the standard Reg T Margin and Portfolio Margin. Note that as Portfolio Margining generally provides for greater leverage, accounts must report minimum net liquidating equity of at least USD 110,000 to qualify for this margin treatment and USD 100,000 in order to enter margin increasing transactions.

Also note that requests for margin upgrades are subject to a Compliance review to ensure that the account holder maintains the appropriate qualifications. This review typically takes between 1 -3 business days to complete.

What formulas do you use to calculate the margin on options?


There are many different formulas used to calculate the margin requirement on options.  Which formula is used will depend on the option type or strategy determined by the system.  There are a significant number of detailed formulas that are applied to various strategies.  To find this information go to the IBKR home page at www.interactivebrokers.com.  Go to the Trading menu and click on Margin.  From the Margin Requirements page, click on the Options tab.  There is a table on this page which will list all possible strategies, and the various formulas used to calculate margin on each.


The information above applies to equity options and index options.  Options on futures employ an entirely different method known as SPAN margining.  For information on SPAN margining, conduct a search on this page for “SPAN” or “Futures options margin”. 

How do you calculate margin requirements on futures and futures options?


Futures options, as well as futures margins, are governed by the exchange through a calculation algorithm known as SPAN margining.  For information on SPAN and how it works, please research the exchange web site for the CME Group, www.cmegroup.com.  From their web site you can run a search for SPAN, which will take you to a wealth of information on the subject and how it works.  The Standard Portfolio Analysis of Risk system is a highly sophisticated methodology that calculates performance bond requirements by analyzing the “what-ifs” of virtually any market scenario.


In general, this is how SPAN works:

SPAN evaluates overall portfolio risk by calculating the worst possible loss that a portfolio of derivative and physical instruments might reasonably incur over a specified time period (typically one trading day.) This is done by computing the gains and losses that the portfolio would incur under different market conditions.  At the core of the methodology is the SPAN risk array, a set of numeric values that indicate how a particular contract will gain or lose value under various conditions. Each condition is called a risk scenario. The numeric value for each risk scenario represents the gain or loss that that particular contract will experience for a particular combination of price (or underlying price) change, volatility change, and decrease in time to expiration. 

The SPAN margin files are sent to IBKR at specific intervals throughout the day by the exchange and are plugged into a SPAN margin calculator.  All futures options will continue to be calculated as having risk until they are expired out of the account or are closed.  The fact that they might be out-of-the-money does not matter.  All scenarios must take into account what could happen in extreme market volatility, and as such the margin impact of these futures options will be considered until the option position ceases to exist.  The SPAN margin requirements are compared against IBKR's pre-defined extreme market move scenarios and the greater of the two are utilized as margin requirement.

When I sell stock, how much does it increase SMA?


When an account holder sells a marginable security, it will typically increase their SMA by 50% of the value of the security sold.

Is there a way in TWS that I can prevent myself from making trades that cause my cash balance to go negative?


There isn’t a function in TWS that prevents account holders with margin accounts from making trades that cause their cash balance to become negative, which would then incur interest charges for a margin loan.  Traders would want to ensure that their cash balance always remained positive or open a cash account.  Negative cash balances are disallowed in cash accounts and orders that would cause the cash balance to go negative should be rejected by the system.

Syndicate content