The commission paid to the gallery is a selling expense that reduces the sales proceeds reported for the transaction. Thus, the commission effectively reduces the amount of gain (or increases the amount of loss) for the sale.
A sale of property that allows for tax deferment if at least one payment is received after the end of the tax year in which the sale occurs. The installment method does not apply to year-end sales of publicly traded securities. Dealers may not use the installment method. Investors with very large installment balances could face a special tax.