# Options Margin Calculation Explained

Options Margin Calculation Explained

The AvaOptions platform calculates required margin using one of two methods, depending on the underlying instrument.

For equity index options, margin uses a simplified exchange margin model. Margin = Margin Rate x Index price x (Total Spot Quantity + Total Short Options Quantity) + Total Option Premium received.

• Example 1: Account has sold 30 US500CASH Puts at \$6.00 for total premium \$180 at a margin rate of 1.5%, with the index trading at 4100. Margin = 1.5% x (30 x 4100)  + 180 =  \$2025.
• Example 2: Account has sold 30 US500CASH Calls at \$7.50, and also has a long position in 10 US500CASH Spot, Margin = 1.5% x (40 x 4100) + 225 = \$2685.

Note that the margin rate for Spot can be different than the margin rate for Options. If an account combines Spot and Options positions in the same underlying, the Spot margin rate is used for both.

For trades in other instruments such as FX and Gold and Silver, margin is set according to the riskiness of the portfolio, applying standardized stresses to each currency pair using a system known as SPAN, for Standardized Portfolio Analysis.

Here’s how it works. We break down your portfolio by currency pair and then assess the value of each pair under 16 different scenarios:

 Spot Price Change Volatility Change % of Risk Down Margin% Up 100% Down Margin% Down 100% Down 2/3 Margin% Up 100% Down 2/3 Margin% Down 100% Down 1/3 Margin% Up 100% Down 1/3 Margin% Down 100% Unchanged Up 100% Unchanged Down 100% Up 1/3 Margin% Up 100% Up 1/3 Margin% Down 100% Up 2/3 Margin% Up 100% Up 2/3 Margin% Down 100% Up Margin% Up 100% Up Margin% Down 100% Up 2 * Margin% Unchanged 35% Down 2 * Margin% Unchanged 35%

Scenarios 1-14 evaluate your portfolio with changes in market volatility at seven different levels: -1%, -.67%, -.33%, Unchanged, +.33%, +67%, and +1%. For instance, if the margin requirement for a currency pair is 1%, these are the seven levels we look at.

Scenarios 15 and 16 consider a market movement up and down by double the margin requirement (e.g. 2%), then take 35% of any portfolio change as the risk. These scenarios aim to capture the risk associated with options that could lose more value without affecting the margin for spot positions.

The biggest loss from these 16 scenarios is taken as the margin for each currency pair. Adding up all the margins for each currency pair gives you the total Required Margin.

Please note that for a portfolio composed solely of spot positions, the SPAN margin is identical to the Margin% multiplied by the total spot position. This aligns with most spot trading platforms, and neither implied volatilities nor scenarios 15 and 16 impact this.

In AvaOptions platform each option’s implied volatility (a measure of the market expectation of price change) is adjusted using the following formula:

Vol Shift = Volatility Factor X Max(Implied Vol, Minimum Vol)

Here, Implied Vol refers to the current mid-market implied volatility of the option, and the Minimum Vol is set at 10%.

Table of Volatility Factors:

 Days to Expiration G10 EM 7 31% 41% 14 22% 29% 30 15% 20% 90 9% 12%

For instance, for a 2-week G10 option, the implied volatility can be adjusted up or down by 22%, but in steps of no less than 2.2. For a 6-month option, it’s adjusted by 9%, but in steps of no less than 0.9.

The Volatility Factor serves to balance out the volatility of volatility, as a 1-week option’s implied volatility can change more drastically than a 1-year option’s. Its calculation involves the following formula:

Volatility Factor = SQRT( 30/ADTE ) * Reserve

In this formula, ADTE refers to the Days to Expiration, with a minimum of 7 and a maximum of 90. The Reserve is set at 15% for G10 currency pairs and 20% for pairs that include one or more emerging market currencies.