As shown by this article, no one actually knows how much these collateralized debt obligations are actually worth.

What happens if the $800 million of securities sells for $700 million? What if they sell for $400 million? What if they sell for less?

A number of funds, and possibly firms, could become insolvent over night.

Bear Stearns Fund Collapse Sends Shock Through CDOs

By Mark Pittman

June 21 (Bloomberg) — Merrill Lynch & Co.’s threat to sell $800 million of mortgage securities seized from Bear Stearns Cos. hedge funds is sending shudders across Wall Street.

A sale would give banks, brokerages and investors the one thing they want to avoid: a real price on the bonds in the fund that could serve as a benchmark. The securities are known as collateralized debt obligations, which exceed $1 trillion and comprise the fastest-growing part of the bond market.

Because there is little trading in the securities, prices may not reflect the highest rate of mortgage delinquencies in 13 years. An auction that confirms concerns that CDOs are overvalued may spark a chain reaction of writedowns that causes billions of dollars in losses for everyone from hedge funds to pension funds to foreign banks. Bear Stearns, the second-biggest mortgage bond underwriter, also is the biggest broker to hedge funds.

“More than a Bear Stearns issue, it’s an industry issue,” said Brad Hintz, an analyst at Sanford C. Bernstein & Co. in New York. Hintz was chief financial officer of Lehman Brothers Holdings Inc., the largest mortgage underwriter, for three years before becoming an analyst in 2001. “How many other hedge funds are holding similar, illiquid, esoteric securities? What are their true prices? What will happen if more blow up?”

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