Premium on bonds payable (or bond premium) occurs when bonds payable are issued for an amount greater than their face or maturity amount. This is caused by the bonds having a stated interest rate that is higher than the market interest rate for similar bonds.
To illustrate the premium on bonds payable, let's assume that a corporation prepares to issue bonds with a maturity amount of $10,000,000 and a stated interest rate of 6%. However, when the 6% bonds are actually sold, the market interest rate is 5.9%. Since the bonds will be paying investors more than the interest required by the market ($600,000 instead of $590,000 per year), the investors will pay more than $10,000,000 for the bonds. If we assume the investors pay $10,150,000 for the bonds, the corporation will record the transaction with a debit to Cash of $10,150,000; a credit to Bonds Payable of $10,000,000 and a credit of $150,000 to Premium on Bonds Payable (an adjunct liability account).
Over the life of the bonds, the $150,000 premium is to be accounted for as a reduction of the corporation's interest expense. This is done through the amortization of premium on bonds payable.
The combination of 1) the unamortized credit balance in the account Premium on Bonds Payable, 2) the unamortized debit balance in the account Bond Issue Costs, and 3) the $10,000,000 credit balance in Bonds Payable is known as the book value or the carrying value of the bonds payable.