Okla. Stat. tit. 11, § 11-36-304: Delivery of bonds to contractor

The cash prepayments and the bonds in the amount that may be

necessary for the purpose shall be turned over and delivered to the

contractor or assigns at par and accrued interest in payment of the

amount due, including advertising, engineering and appraising costs,

in accordance with the terms of the contract. The bonds shall be

executed and held by the municipality and delivered in parcels from

time to time upon the completion and approval of the work, or any

part thereof not less than one (1) block, in an amount equal to the

improvement so completed and accepted.