The regulators and industry didn't really get worked up until the credit crunch hit money market mutual funds. Think about it. Via the alchemy of securitization, some quite risky assets were pooled into AAA rated bonds that found their way into the money market mutual funds that have been touted by the industry and many banks as ultra safe for retail customers. The reputation for safety is so great that many assume they are covered under FDIC protections. This is where the credit crunch ensnares your grandmother. Fortune points out that by law these funds are required to invest in securities with "minimal credit risks." Did high credit ratings render them such. Once again, the agencies find themselves in the hot seat.  

For more:
- here's the Fortune article