What FASB does for the United States is it creates what are called Generally Accepted Accounting Practices.

财务会计准则委员会为美国所做的贡献,就是制定了国际公认会计准则

耶鲁公开课 - 金融市场课程节选

When the Financial Accounting Standards Board listens to what corporations are saying and helps them-- it adjusts these standards from time to time but it does have definitions that have to be maintained.

财务会计准则委员会,听取公司的意见并协助他们...,并且适时调整标准,不过有些规则始终如一

耶鲁公开课 - 金融市场课程节选