Updates with response from Wisconsin's insurance regulator.)

NEW YORK (

TheStreet

) --

Ambac Financial Group's

(ABK)

Chief Financial Officer resigned today, almost a week after the company said it misstated information in regulatory filings.

Sean Leonard has stepped down to pursue other interests, Ambac said in a statement, without elaborating. Ambac spokesman Peter Poillon said in an interview that Leonard's departure was unrelated to issues stemming from

incorrect information

supplied to the Wisconsin Office of the Insurance Commissioner about its bond insurance business.

Ambac Assurance

, the company's main operating unit, said in a regulatory filing last week that it understated impairment charges for credit default swaps earlier this year. If the charges had been accurate, Ambac would have failed to meet capital requirements in Wisconsin for the first and second quarters. Ambac also counted $520 million made from fourth-quarter transactions toward its third-quarter results.

Wisconsin Insurance Commissioner Sean Dilweg declined to comment about Leonard's departure, according to spokesman Jim Guidry.

Ambac executives met

with Wisconsin regulators late last week.

Chief Executive Officer David Wallis will oversee Leonard's responsibilities until his replacement is named. Ambac hasn't set a deadline for appointing a new CFO and, according to Poillon, an internal candidate is could be promoted. Leonard joined Ambac in 2005. Wallis called him a "valuable and hard-working member of the executive team" in the statement.

Ambac shares have dropped 9.9% today to 81 cents. They've fallen 34% in the past year, while the

S&P 500 Index

advanced 38%.

--

Reported by Gavin Magor in Jupiter, Fla.

Gavin Magor is the senior analyst responsible for assigning financial-strength ratings to insurance companies. He conducts industry analysis and supports consumer products. Magor has more than 22 years of international experience in operations and credit-risk management, commercial lending and analysis. His experience includes international assignments in Sweden, Mexico, Brazil and the U.S. He holds a master's degree in business administration from The Open University in the U.K.