In general, a change in accounting method must be approved by the IRS. For income tax purposes, a taxpayer must use the same accounting method, either percentage of completion or completed contract method, for all long- term contracts in the same trade or business. A taxpayer does not have to impute interest on a receivable from sales if payment is to be made within six months. The installment method is not applicable to sales of inventory and marketable securities Interest is not imputed on a gift loan between two Choose... # Choose... Choose... Choose...