For example, say a really good futures trader hit it big and made $1,000,000 in profit one year just trading S&P 500 contracts on symbols like the MES or ES. Their total winning trades amount to $2,000,000 and their total losing trades amount to -$1,000,000 leaving them with the $1,000,000 (yearly PNL) profit in aggregate gains mentioned in the first sentence.
In this scenario would this trader, come tax season, report and pay taxes on only...
A) the aggregate gain of the $1,000,000 (Yearly PNL) profit.
or
B) the total winning trades amount of $2,000,000.