The three parties
A construction surety bond involves three parties. The contractor is the principal, the project owner or general contractor requiring the bond is the obligee, and the surety company provides the guarantee. The surety promises the obligee that the contractor will meet the bonded obligation, subject to the bond and contract terms.
三方關係
建築工程保證保險涉及三方：承包商是被保證人（Principal）；要求保證的項目業主或總承包商是受益人（Obligee）；保證公司（Surety）則提供擔保。根據保證書及合同條款，保證公司向受益人承諾承包商會履行受保證的責任。
Bid bond
A bid bond supports the contractor’s promise that its bid was submitted in good faith and that, if accepted, it intends to enter the contract at the bid price and provide the required contract security. A contractor should arrange its surety relationship before bidding—not assume a bond can be obtained after the award.
投標保證（Bid Bond）
投標保證用來支持承包商的承諾：投標是善意提交；如果中標，承包商有意按照投標價格簽訂合同，並提供招標文件要求的合同保證。承包商應在投標前建立保證額度，而不是中標後才假設一定能取得保證。
Performance and payment bonds
After award, a performance bond may protect the obligee from financial loss if the contractor fails to perform the contract as required. A labour and material payment bond guarantees covered payment obligations to eligible subcontractors, labour and material suppliers. These bonds serve different purposes and their exact response depends on the wording.
履約保證及勞工材料付款保證
中標後，如果承包商未能按合同要求履約，履約保證（Performance Bond）可能保障受益人的相關財務損失。勞工及材料付款保證（Labour and Material Payment Bond）則擔保向符合資格的分包商、勞工及材料供應商履行受保付款責任。兩種保證目的不同，實際保障取決於保證書條款。
Why it is closer to credit than insurance
A surety expects the contractor to complete the work and repay the surety for losses or expenses if the surety must respond. Contractors—and sometimes owners or other indemnitors—may be required to sign an indemnity agreement. That is why underwriting resembles a credit and business-capability review more than simply buying an insurance policy.
為何更接近信貸而非一般保險
保證公司預期承包商能完成工程；如果保證公司必須作出賠付或承擔費用，承包商通常須向保證公司償還。承包公司，以及在某些情況下的公司股東或其他彌償人，可能需要簽署彌償協議。因此，核保過程更像信貸及企業履約能力審查，而不只是購買一般保險。