Contract Guarantee is the London Market using the Code of Practice for Contractual Assurance which was created by its Market Reform Group. Essentially, the idea of contract certainty is that each party will know exactly what the product being sold is at the time it is sold, so it can be priced right and the buyer knows exactly what he is buying without any or subsequent misunderstandings. . Now, in accordance with contractual certainty, the terms “to be agreed” must be agreed by the date of the reinsurance contract. In the United States, the finality or certainty of a contract has not yet been established at the level of the London Market Code of Practice for certainty of a contract. The 9-month rule, which actually derives from Part 23 of SSAP 62, requires a reinsurance contract to be in writing and signed within 9 months of policy commencement, but allows the contract to take effect before the contract is entered into.