(1) Public Improvement Contracts. Bid security in the amount of 10 percent of the bid shall be required for public improvement contracts where the amount of the contract exceeds $100,000. The bid security shall be forfeited if the bidder fails to execute the contract promptly and properly if awarded.

(2) Other Public Contracts. Bid security not to exceed 10 percent of the bid may be required by the City for other contracts in order to guarantee acceptance of the award.

(3) Form of Bid Security. The following forms of bid security will be accepted by the City:

(4) Return of Bid Security. The bid security of all unsuccessful bidders shall be returned after a contract has been executed, or all bids have been rejected.