Bid deposits

(a) All bids shall be accompanied by a deposit of legal tender or by a certificate of deposit, share certificate, cashier's check, treasurer's check, teller's check, or official check drawn by, or a certified check accepted by, a bank, savings institution, or credit union insured by the Federal Deposit Insurance Corporation or the National Credit Union Administration, in a sum not less than five per cent of the amount bid, payable at sight or unconditionally assigned to the officer advertising for tenders; provided that when the amount bid exceeds $50,000, the deposit shall be in a sum not less than $2,500 plus two per cent of the amount in excess of $50,000. If the bid deposit is in the form of a surety bond, it shall be issued in accordance with subsection (b). (b) A bid may be accompanied by a surety bond executed to the officer calling for bids by the bidder as principal and by any bonding company listed in the United States Treasury List; provided that the bond furnished by any surety listed shall not exceed the bonding capacity rating of that surety on the Treasury List; in a sum of equal amount, conditioned upon the bidder entering into the contract and furnishing satisfactory security within ten days after the award or within any further time as the officer may allow, if the bidder is awarded the contract.