The cost basis of a is calculated by multiplying the total number of (either or by the average per share Here are some examples for calculating cost basis:
1. If you own 100 shares of XYZ at $10 per share your cost basis would be 100 x $10 = $1000
2. If you are short 100 shares of XYZ at $10 per share and short 100 more at $15 per share, your cost basis would be 200 total shares multiplied by the average sale price per share ($10 + $15) ÷ 2 = $12.50.
200 x $12.50 = $2500
The cost basis for is calculated by multiplying the by the number of shares per contract (usually 100), multplied by the number of contracts. You use the break-even because it represents your entry price if you were to or get shares. For example, if you sold 2 at a $10 for $1 (making your break even $9), your cost basis would be calculated by multiplying your $9 break even by 100 shares per contract by a total of 2 contracts.