The value and profit or loss (P/L) of your options positions are all calculated based on the mark price. The mark price is a reference price used to determine the fair value of an option.
There are two ways to find the mark price of an option:
1. Go to the options' quotes page.
2. Check the options chain.
Mark Price Calculation By Options Type:
| Options Type | Mark Price Calculation |
| US Stock Options and Index Options | Mark Price = (Best Bid + Best Ask) / 2 |
| Hong Kong Stock Options and Index Options | Mark Price = Last Price, unless: • If Best Ask < Last Price, then Mark Price = Best Ask • If Best Bid > Last Price, then Mark Price = Best Bid |
| Futures Options |
US options are now connected to OCC (Options Clearing Corporation) settlement prices. After the US market closes (generally at 8:00 PM ET on trading days), we will update the market value of your US options positions using the official OCC settlement price.
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