Prompt Payment Amendments of 1986

Prompt Payment Amendments of 1986 - Revises Federal law to deem the head of an agency to receive an invoice on the fifth day after the date on which a property is actually delivered, or final performance of a service is actually completed, unless the contract specifies otherwise.

Makes Federal prompt payment provisions applicable to the United States Postal Service.

Reduces the 15-day grace period for payment of interest penalties to eight days for solicitations issued before October 1, 1988. Requires an agency to pay a double interest penalty if it fails to meet such grace period and the business concern makes a written demand that the agency pay such penalty. Makes the interest penalty provisions applicable to construction contracts for progress payments and retained amounts.

Specifies the calculation of time for interest penalties on discount payments.

Revises agency reporting requirements on interest penalty payments to include a description of agency payment practices.

Requires the modification of Government-wide procurement regulations to implement Federal prompt payment provisions.