48 C.F.R. § 32.103
When satisfactory progress has not been achieved by a contractor during any period for which a progress payment is to be made, a percentage of the progress payment may be retained. Retainage should not be used as a substitute for good contract management, and the contracting officer should not withhold funds without cause. Determinations to retain and the specific amount to be withheld shall be made by the contracting officer on a case-by-case basis. Such decisions will be based on the contracting officer's assessment of past performance and the likelihood that such performance will continue. The amount of retainage withheld shall not exceed 10 percent of the approved estimated amount in accordance with the terms of the contract and may be adjusted as the contract approaches completion to recognize better than expected performance, the ability to rely on alternative safeguards, and other factors. Upon completion of all contract requirements, retained amounts shall be paid promptly.
48 C.F.R. §32.103