More financial guaranty insurance companies are part of publicly owned holding companies, according to a new report published today.

Standard & Poor’s wrote that as the newer companies matured, investor circumstances have changed, leading to the new ownership structure.

Last year three financial guaranty insurance holding companies added a public equity component to their ownership structure, while one increased its public ownership component.

Ambac Financial Group Inc. and MBIA Inc. are examples of companies that are 100 percent publicly owned.

S&P analyst and report author Robert Green said that public ownership does not lend itself to the capitalization of start-up or newer bond insurers, “and it certainly didn’t lend itself to capitalization when this industry and the financial guaranty concept were new.”

“Theoretically, a combination of both public and highly rated strategic ownership, where the strategic owner has a material investment, may be the best possible ownership profile,” Mr. Green wrote.

The next most desirable ownership structure was 100 percent strategic ownership. “Ideally, strategic owners are highly rated and view the financial guaranty unit as bringing benefits to the consolidated operations beyond earnings,” he wrote.

But having only one strategic owner could pose a challenge if that owner should suffer a ratings downgrade, such as the case with XL Capital.

Both majority and 100 percent public ownerships have their downside in that market conditions or adverse development at the bond insurer may make it difficult for management to sell shares at an unattractive price.

“Another challenge associated with the public equity market is the strong emphasis placed on quarterly results by market participants,” Mr. Green said.