Just like any other income it is taxed by both the state & the feds at the tax rates they determine ... so yes, you could be paying 15% to both taxing authorities.
Hawaii Capital Gains Tax
You will pay either 0%, 15% or 20% in tax on long-term capital gains (which are gains that are realized from the sale of investment you held for at least one year). Short-term capital gains are taxed at the full income tax rates listed above.
