Money market mutual funds are just as vulnerable to the temperaments of Wall Street.

You can't trust the money market mutual fund pledge not to break a buck — at least not with your safe money, the money you depend on to be there in tough times like 2008.

When it comes to money market mutual funds, you can't trust the pledge not to break a buck — at least not with your safe money, the money that's supposed to be there in tough times like 2008.