While retention oftainment in the construction industry has become a fairly standard practice, it is not necessary. And this is certainly not an advantage for the subcontractor. The AIA® document A401™ is the standard form for an agreement between the contractor and the subcontractor intended to justify the contractual relationship between the contractor and the subcontractor. Aia contract documents are standardized forms applicable to many projects, commercial or private. For subcontractors, the most common AIA contract is the standard form A401 for agreements between contractors and subcontractors. While the subcontractor usually does not have to pay for the contract itself, they may have to pay for changes to the document. It is likely that subcontractors will also have to pay for payment receipts required by the contract.