retention sum指质保金、保留金，等于retention money。承包方交付的工程（货物）一般有一个质保期，质保期根据合同性质长短不一，比如有的货物有3年的质保期，有的工程可能有5年的质保期，有的可能有5年的质保期，有的可能就2年的质保期。根据合同约定，一般在质保期间承包方应该免费（视合同具体情况而定）对其交付的工程（货物）进行维修或替换。如果在工程（货物）交付之时就把所有的合同款项支付给承包商，则承包商的权利已经全部实现，其履行合同质保义务的积极性会受到很大影响，发包商就也失去了可以制约承包商的砝码。因而，质保金可以作为制约货物提供方的砝码。一般占合同总价5%-10%。

其英文释义如下：

Retention sum in a construction contracts is to empower the employer to retain a stipulated percentage of each payment which becomes progressively due to the contractor. The purpose of retention sum is to protect the Employer in the event when the contractors fails or defaults in its performance under the contract, such as abandonment or the works is of poor or defective quality. In most of the construction contract, the retention sum is apportioned into two moieties, the first moiety will be released upon Certificate of Practical Completion (“CPC”) of the Construction Project and the second moiety being released upon the issuance of Certificate of Making Good Defects (“CMGD”).

如：

Retention Sum means the sum of Ringgit Malaysia Six Hundred Twenty Two Thousand and Five Hundred (RM622,500.00) only representing three per centum (3%) of the Purchase Price;

质保金指购买价格的百分之三（3%），即陆拾贰万贰仟伍佰马来西亚林吉特（RM622,500.00）。

质保金/保留金可以保函的形式交付：

保留金保函(Retention Bond)或质保函(Warranty Bond)

质保金/保留金保函和质保函虽然名称不同，但一般均指保证承包商或卖方履行工程承包项目或货物买卖项目的质保期内义务的独立保函。在工程承包项目或货物买卖项目中通常会要求扣留一定比例的合同价格，作为保证承包商或卖方履行工程承包项目或货物买卖项目的质保期内义务的担保，发包人或买方有权在承包商或卖方未依约履行合同义务的情形下相应扣减质保金。保留金保函和质保函通常用于替代质保金，使得承包商或卖方可早日收到货款，减少资金占用，并且使得发包人或买方获得一定的保障。

如：

This Five percent (5%) of the SUBCONTRACT PRICE may be paid after Completion of the WORK against a Retention Bond as per Article 6.

按照第六条规定，工程竣工后，可能要使用保留金保函支付分包合同价格的百分之五（5%）。