The gain or loss on each asset is figured separately. The sale of capital assets results in capital gain or loss.In this article, we discuss what asset sales are, how they work and how to calculate a loss or gain because of an asset sale. Asset Sale Planning. When we're talking about the gain or loss of the sale of an asset we need to be looking at net book value at the time of the sale. In an asset sale, the new owner purchases the business's physical assets. The seller retains all rights to the legal entity. Learn the tax implications for each type of sale.