Today, there are many municipal bonds that were originally sold to expire 10-15 years from now. But projects finished early and the issuers wanted to pay them off. However, the bonds often have a minimum time before they can be called. So, issuers simply buy US Treasuries and put them into the bond, to be used when the bond can be called. Now, for all intents and purposes this is a US government bond which has the added value of being tax-free. I had a friend, John Woolway, send me some of the bid and ask prices for these type of bonds. One is paying two times what a normal US Treasury would pay. Another is paying 291% of a normal US Treasury. And it is tax-free! Why would anyone sell what is essentially a US treasury bond for a discount? Because they are being forced to sell, and no one is buying! The credit markets are frozen.