NEGATIVE LUCAS HOOD: Short-term capital gains tax rates apply to gains on the sale of investment that you owned for a year or less. You'll pay your ordinary federal income tax rate on short-term capital gains, and that tax rate depends on your income-tax bracket.
The 15% tax rate is only for long-term capitol gains (investments held for a year or longer). Those in the top bracket pay 20% (plus a 3.8% healthcare tax).
Short-term capitol gains (investments held for less than a year) are taxed as regular (work) income. So there is no advantage for these investments. Those in the top tax bracket pay 39.6% (the highest rate, plus a 3.8% healthcare tax).
Overall, the picture isn't so rosy for short-term capitol gains!