Hello, Suppose selling a stock has a $5 transaction fee ($5 buy, $5 sell). Do you marry each transaction cost to the security buy/sell? Or do you simply add up all the transaction fees you incurred for that quarter and deduct them from any capital gains that quarter? For example, supposed you bought a stock for $1000, and it had a $5 fee to buy the stock. Then you sold it for $1100, but also had a $5 selling fee. So it would look like this: ($1100 -$5) - ($1000 + $5) = $1195 - $1005 = $90 capital gain. The other style would be something this: $1100 - $1000 = $100 capital gain $30 trading fees for the month (however they happened to arrive). So you have $100 - $30 = $70 capital gains after fees.