Three of Ambac Financial Group Inc’s top ten shareholders are calling on its new CEO Nader Tavakoli to step down, according to people familiar with the matter. One of the reasons they give is that he is slow to settle $4 billion in insurance claims in which at least two of them have an interest, the sources said.

The policy claims relate to complex financial instruments, including secured mortgage backed securities, that were insured by Ambac and were at the center of the 2008 financial crisis. It is unclear what portion of the claims have been acquired by the shareholders or what they paid for them.

The sources asked that the names of the shareholders, who have communicated with the company verbally and through at least one letter, not be identified.

In the past, the policy claims have traded as low as 20 cents on the dollar. They currently trade at close to 80 cents, but it is far from clear whether that market could withstand any substantial trading without pushing prices lower. The shareholders point out that Ambac bought back some claims as recently as last June for more than 90 cents on the dollar, and argue the company should do so again.

Ambac spokeswoman Abbe Goldstein said that “the vast majority of shareholders” it had talked to support the board’s decision to appoint Tavakoli.

Tavakoli, who was named CEO earlier this month after serving as interim CEO for a year, declined to comment.

The spat represents one of the biggest challenges the bond insurer has faced since it emerged from bankruptcy in 2013. It is a shadow of its former self as a result of getting badly roiled in the 2008 financial crisis, and is currently worth just $552 million, down from $1.6 billion two years ago and around $10 billion in 2007.

Corporate governance experts said it was permissible for shareholders to push for action that could also favor them as a creditor. “Legally, if a stock holder has another interest – financial or otherwise – they may advocate in favor of that self interest even if that is not in the interest of the company or other shareholders,” said law professor Jill Fisch at University of Pennsylvania’s Law school.

Concern About Liabilities

The shareholders have called on the company to ask its regulator, the Commissioner of Insurance of the State of Wisconsin, to accelerate Ambac’s settlement of the claims. They have also suggested Ambac buy back the claims itself in the open market or offer policy holders cash for their policies, in a practice known in the industry as a commutation.

Ambac’s Goldstein said that any change in the payouts schedule is solely at the discretion of the commissioner.

The commissioner declined to comment.

Ambac has publicly resisted calls to speed up its payment of the claims, citing concerns that it wouldn’t be able to meet its liabilities that extend out to 2054. The liabilities, which could run into the tens of billions of dollars, include claims that cover debt issued by the city of Chicago, student loans and military housing, as well as Puerto Rico.

The shareholders argue that by paying the claims earlier, Ambac will save on the interest that would otherwise accrue and would not have to pay face value when the claims mature.

The sources said the three shareholders are frustrated not only with the handling of the policy claims but with the company’s inability to get Countrywide Home Loans Inc, Bank of America Corp and JPMorgan Chase & Co to settle lawsuits brought by Ambac. The company sued the banks over losses on a portfolio of subprime mortgages it insured prior to the financial crisis. The shareholders say that based on similar settlements, Ambac could yield $2.6 billion or more in any agreement with the banks.

Bank of America, which acquired Countrywide during the financial crisis, and JPMorgan offered no comment.

The sources said that the three shareholders believe that such action by Ambac would boost its battered shares, which ended trading on Tuesday at $12.42, down by more than half in the past year, amid concerns about the company’s exposure to Puerto Rico’s debt crisis.

Compensation Questioned

The company said in its most recent earnings conference call that it is trying to find ways to free it from the burden of the troubled insurance policies.

The shareholders also point to Ambac’s acquisition of hundreds of millions of dollars of insurance claims in 2014 under the previous CEO, Diana Adams, as evidence the company could do so again. Adams declined to comment.

The shareholders also question whether Tavakoli has the support of the board of Ambac’s insurance subsidiary, as he has not been named as CEO of that unit. His predecessor was CEO of both the holding company and the operating business.

The shareholders have also criticized Tavakoli for his compensation, which could reach up to $4 million for 2015 if he is given the maximum bonus allowed by his contract. They argue that Tavakoli stands to make more than $9 million for his work in 2016, whereas Adams’ employment contract only allowed for maximum $2 million in compensation.

Tavakoli declined to provide a comment on the insurance unit or his compensation.