Final answer:
The concept governing GAAP related to recording gain contingencies is conservatism, which suggests caution and avoiding overestimation of assets or income.
Step-by-step explanation:
The underlying concept governing the generally accepted accounting principles (GAAP) pertaining to recording gain contingencies is conservatism. This principle advises accountants to proceed with caution when faced with uncertainty and to avoid overestimating assets or income. Therefore, gain contingencies are not recorded until they are realized or realizable, adhering to the conservative nature of accounting practices. This ensures that financial statements do not overstate the financial position of a company.