Earlier quoted context omitted.
Some institutions are obligated (by charter or contract) to only buy AAA rated bonds. That's why it's a big deal... Now that being said, I have no idea how this would work in practice.
I'm sorry but that's bull. Anything can be changed. Contracts can be revised and even charters can be updated by a Board of Directors. If you hold a significant amount of U.S. Bonds you aren't going to ditch them on S&P's say so. You're going to call a meeting of the Board of Directors or Trustees or whoever and decide based on your own judgement. The whole point of a rating agency is to provide you with research tha…
While that may have been true a couple of years or may be even months ago, I'd say that this is anything but certain. There are a lot of people and government through out the world who would like to see the U.S. weakened.