[lotsofpulp]

Based on the consequences to the ratings agencies of fraudulently (or erroneously) rating mortgage debt in 2000s, there are no laws requiring ratings agencies to be accountable to anyone.

The sellers of the debt, or financial products, are the ones that pay the ratings agencies, so they are the real customers.

The buyers should be doing due diligence, especially considering the conflict of interest, but they are also frequently agents on behalf of taxpayers (for government pensions) or other far removed investor, so agency risk is big here too.