能把過去賠的都抵掉

Capital gain is capital gain, no matter it comes from real estate, stock, bond or baseball cards. 

Capital gain/loss has only two categories, long term (>12 months) and short term (<12 months)

Long term capital gain should be deducted from long term capital loss first, then if there is left over, the left over long term capital gain can be deducted from short term capital loss.