Which organization is known for its credit rating services?

The organization known for its credit rating services is Moody's Investor Service. This firm specializes in assessing the creditworthiness of borrowers, including governments, corporations, and other entities, by providing credit ratings. These ratings are essential for investors to understand the risk associated with investing in particular bonds or debt instruments. Moody's plays a crucial role in the financial markets, as its ratings influence borrowing costs and investment decisions.

The other organizations listed serve different purposes: the Federal Reserve is the central bank of the United States and focuses on monetary policy; the Internal Revenue Service is responsible for tax collection and tax law enforcement; and the Government Accountability Office provides auditing, evaluation, and investigative services for the United States Congress. None of these organizations is involved in the credit rating process in the same way that Moody’s is.