When calculating the cost basis for stock, can you use both the commission to purchase the stock and the commission to sell the stock?

[JohnW15 · Accepted solution]

You can use each separate commission for each transaction -- in determining the cost basis, and then in computing the sales price. 

For example:

The tax basis of stock you purchase is what you pay for it, plus the commission you pay. Say you buy 100 shares of XYZ Inc. at $40 a share, and you pay a $100 commission. The total cost is $4,100 and the tax basis of each of your shares is $41.

If you sell the 100 shares for same $40 each, and pay $100 commission on the sale, you have a $200 loss—your $4,100 basis minus the $3,900 proceeds of the sale.

[mlk23]

Thanks for the great explanation.

[fanfare]

your broker does all this arithmetic for you on your 1099-B. There is nothing for you to do but copy the numbers.