Bloomberg News reports that Moody's (NYSE: MCO) may downgrade municipal bond insurer MBIA (NYSE: MBI) after it reported deepening losses from the mortgage-market slump. MBIA's insurance financial strength rating may fall to the Aa range, although a drop to the A category is possible. MBIA's stock is down 91% since the end of May 2007.

That's when I first suggested that investors consider selling MBIA shares short. William Ackman had already shorted MBIA because he thought it lacked the capital needed to support its obligations. Back then, MBIA traded at $66.59 a share -- today it's down to $5.88. His bet proved prescient.

Meanwhile, investors are wagering that MBIA won't make it. Credit-default swaps tied to MBIA's insurance unit rose to a record as investors hedged against the risk the company's guarantees will sour. Sellers of five-year contracts demanded 23% upfront and 5% a year. That's up from 18.5% initially and 5% a year yesterday.

Only $5.88 more to go.

Peter Cohan is President of Peter S. Cohan & Associates. He also teaches management at Babson College and edits The Cohan Letter. He has no financial interest in MBIA securities.