Ambac to Raise $1.5 Billion To Keep Triple A Rating

Ambac Financial Group's plan to raise up to $1.5 billion in capital is nearly complete, bankers say, which should help the troubled bond insurer keep its crucial triple A debt rating.

Ambac said it will raise up to $1 billion through a public offering of common stock and an additional $500 million through the sale of equity units. Bankers involved in the deal said the common stock offering is already "oversubscribed" and the $500 million offering should sell easily.

Ambac also said it would cut its common dividend and stop insuring risky debt for six months.

Both Moody's and Standard & Poor's said they would affirm Ambac's triple-A ratings if the capital-raising is successful. Fitch Ratings, however, said it would maintain its recently lowered double A rating.

Still, even if Ambac raises the money, it will remain on negative credit watch, meaning it could still lose its triple A rating if business conditions don't improve.

Ambac shares , which were halted around midday, fell sharply when trading resumed around 1:20 pm ET. Investors had hoped for a larger contribution from global banks to help Ambac, whose plan will dilute its outstanding shares.

Like other bond insurers, Ambac got into trouble by moving beyond guaranteeing safe municipal bonds and insuring risky subprime-related debt. The resulting loses have threatened Ambac's triple A rating, which it needs to attract new clients.

Ambac's current clients, including many of the banks involved in helping Ambac raise capital, were worried that a downgrade of Ambac would force them to write down more of their own subprime-related debt. Citigroup and Barclays are among the banks helping Ambac that held these risky bonds, known as collateralized debt obligations, or CDOs, enhanced by Ambac's Triple A rating.

Private equity firms with no ties to Ambac were also expected to participate in the recapitalization but are not under the current plan. One private equity firm, Cerberus, is still on the fence, adding to the fears that the offering isnt big enough.

Banks have had to revise earlier bailout proposals for Ambac because some or all of the three major ratings agencies weren't satisfied with the structure given the amount of capital the banks were putting into the transaction.

As reported by CNBC, the initial deal split Ambac into two companies, one that insured municipal bonds and another that insured the risky and price-depressed CDOs. Under a revised plan, Ambac will remain a single entity instead of splitting into a good-bank/bad bank type operation.

MBIA , the largest bond insurer, has recently raised more than $2.5 billion of capital from investors to help offset losses and has taken other measures to boost capital, such as eliminating its dividend.

Still, some analysts are skeptical that even with new capital, downgrades of bond insurers can't be avoided in the future. That's because they may face more losses from insuring CDOs and other bonds that are packed with depressed subprime loans.

People inside the New York State insurance department, which has taken the lead in trying to prop up the insurers, say both MBIA and Ambac have enough assets to cover losses stemming from their insurance of depressed collaterialized debt obligations, or CDOs, held by large banks like Citigroup.

The bigger question is whether these firms can compete with ratings less than triple-A, particularly now that the bond insurance business will be focusing on covering bonds of municipal governments. Many large investors of municipal debt can only hold securities with triple-A ratings.

Meanwhile, a downgrade of MBIA and Ambac could pose big problems for the banks that hold bonds they insure. Analyst Meredith Whitney said recently that the downgrades could cause writedowns of another $75 billion at the big banks.

© 2009 CNBC.com