“S&P is the world’s largest ratings agency. In most cases, its business model is based on charging the issuers of debt–private corporations, local and state governments, for instance–in exchange for a rating. The issuer then uses a positive rating to give investors confidence in the solidity of the investment. But S&P also rates the debt of 126 countries. And, like many of the countries whose debt is rated by S&P, the United States neither requests nor pays for its rating.”
They get their income from the companies they rate. Yeah, no incentive to shade the grades there…