If you entered and exited your positions in the Forex market within 6 months, only 40% of your profits is taxed as short-term capital gains. 60% of your profits get the benefit of being taxed as long-term capital gains. If your profit is $10.000, this means that you will have to pay 33% on $4,000 and 15% on $6,000.

The little example:

Portion taxed as short-term capital gains
$10,000 x 40% = $4,000
$4,000 x 33% = $1,320

Portion taxed as long-term capital gains
$10,000 x 60% = $6,000
$6,000 x 15% = $900

Total taxes paid

$1,320 + $900 = $2,220