I’m hearing from so many of you who have money locked up in Auction Rate Securities, which I wrote about in my column last Sunday.

Those were funds that were marketed as a safe substitute for money market mutual funds, but it turns out they were not at all. The long-term bonds these funds invested in suddenly aren’t selling any more. So investors can’t cash out. And they thought they’d bought a liquid investment!

From those whose money is gone I know the shock is great. Some say they were talked out of FDIC-insured certificates of deposit. Some say the yield wasn’t all that good. Some brokers say they had no idea these funds could blow up this way.

On one side, I do believe that honest brokers didn’t mean to sell explosive funds. On the other, I know these readers didn’t know what they were buying, because the explanations were, to be kind, incomplete. And in the middle, is the money lost.

Never, ever ever buy an investment unless you understand it. And never accept the explanation at face value.

The market for auction-rate securities had never before blown up. Just as the market for subprime loans had never before exploded.