Three days after adopting a poison pill to fend off a hostile bid from Endurance, Aspen sent a letter to its shareholders Sunday restating concerns it first aired hours after the bid was made public last Monday.

The letter is co-signed by Glyn Jones, chairman of the board of Aspen Insurance Holdings Limited, and Chris O’Kane, Aspen’s chief executive officer. The content of the letter, released to the media on Sunday night repeatedly refers to the “proposal” by Endurance Specialty Holdings to acquire Aspen for $3.2 billion by enclosing the word in quote marks, underscoring the Aspen’s view that the “‘proposal’ is merely a request for a one-way option to start an investigation” of Aspen.

The letter also reiterates and expands on questions about:

• Lack of disclosure regarding an outside investment in Endurance, which represents $1.05 billion of the funding of the deal.
• “Dis-synergies” that will bring about a loss of business—a fact that Aspen says has been confirmed in discussions with brokers and clients.
• Endurance’s chief executive officer, John Charman, who Aspen says was booted from prior positions at ACE and AXIS Capital “for his less than collegial attitude.”

Specifically, Aspen’s letter refers to news reports indicating that Charman left ACE Limited in March 2001 “due to ‘personal differences’ and AXIS when the ‘board kicked him out in 2012 without cause.”

The letter also refers to ongoing litigation between the two companies “as a result of Endurance’s orchestrated poaching of Aspen employees,” and cites press reports that Aspen believes indicate a “disdain for Lloyd’s,” which is a core component of Aspen’s business.

Aspen, one of the Bermuda companies that emerged after 2001, was set up by 39 people who used to work at a Lloyd’s business known as Wellington, including O’Kane.

Aspen, Endurance and AXIS Capital are all members of the Bermuda “Class of 2001,” formed in the wake of the 9/11 attacks.

Charman, the former CEO of AXIS, has four decades of global experience in the insurance industry, first as an underwriter and then as a chief executive. He held his first CEO role at Tarquin plc, the parent company of the Charman Underwriting Agencies at Lloyd’s, which was sold to ACE Ltd. in 1998.

While Aspen charges that Endurance’s Charman has shown “disdain for Lloyd’s,” Endurance charges that Aspen’s board is showing disdain for its own shareholders by rejecting a proposal that is priced at a premium to recent share prices and estimated earnings for 2014.

“At a time when the Aspen board should be seriously considering an opportunity to deliver significant value to its shareholders, it is instead focused on blocking them from receiving that value and on taking actions to entrench themselves,” Endurance CFO Michael McGuire said in a media statement on April 17. The statement was Endurance’s latest counter move on April 17—responding to Aspen’s adoption of a poison pill to thwart a hostile takeover announced earlier that same day.

“This is not a surprise given the lack of alignment and clear disdain Aspen’s Board has shown for its shareholders in summarily rejecting our proposal without any discussion whatsoever,” McGuire continued.

Aspen’s Latest Move

In a statement released with the letter on Sunday evening, Aspen Chairman Jones said: “Since Endurance publicized its letter to Aspen on April 14, we have actively reached out to shareholders and have found overwhelming consensus for our rejection of Endurance’s ill-conceived ‘proposal,’ which undervalues Aspen, represents a strategic mismatch and carries significant execution risk.

“Furthermore, our discussions with clients and brokers have confirmed our view that the combination would result in substantial dis-synergies. Mr. Charman’s characterizations are merely an attempt to deflect from the real point that the ‘proposal’ is unattractive and not actionable.”

On April 14, Endurance announced that repeated refusals by Aspen’s board and management to engage in discussions about a potential deal had prompted Endurance to advise Aspen shareholders of its $3.2 billion—$47.50 per share—bid directly. The proposed deal offers Aspen shareholders the right to receive the consideration all in cash, all in Endurance shares or in a cash-stock combination.

“Endurance stock as consideration in a combination is not appealing,” Aspen says in its letter to shareholders, suggesting that Endurance’s current business mix is unattractive and that the quality of Endurance’s earnings is questionable—because earnings have been disproportionately driven by prior-year reserve releases. Reinsurance business at Endurance is weak and insurance business is dominated by the troubled and volatile crop line, Aspen adds.

Noting that Endurance has put a “$100 million figure on “annual synergies” to be derived from a deal combining the two Bermuda companies, Aspen’s letter says that the sources of these synergies remain unidentified.

“Importantly, we believe this claim assumes no disruption or loss of business to the combined company” but clients and brokers confirm that that’s not now a potential deal would play out. “If anything, we appear to have understated the dis-synergies and the impact they would have on the value of the combined company.”

“Scale for the sake of scale is not a reason to pursue a business combination with Endurance,” the letter says.

Turning to questions about an investment from CVC Capital Partners, Aspen says this “will negatively impact the shareholders of both companies.”

Endurance’s Charman, in his letter to Aspen shareholders last Monday said that the cash consideration to be offered to Aspen shareholders “will be funded from Endurance’s substantial cash resources and $1.05 billion of newly issued common shares to investors led by funds advised by CVC Capital Partners Advisory (U.S.), Inc. and its affiliates, which have already completed due diligence on Endurance and the merits of the transaction, and have provided an equity commitment letter to Endurance.”

Aspen’s letter yesterday reveals that Endurance has stated that CVC’s $1.05 billion investment “consists of Endurance shares at a ‘pre-negotiated discount,’ Endurance warrants with an exercise price ‘higher than an average market price’ and ‘customary’ governance rights for a ‘significant’ minority investment.”

The Aspen letter continues: “The amount of equity to be given up to CVC and at what ‘discount[ed]’ price, the amount and terms of the warrants and the ‘customary’ governance rights that CVC would receive all significantly impact the economics of a potential transaction—not just for Aspen and its shareholders, but for Endurance and its shareholders as well.”

Adding that these terms are “extremely important to the valuation of the stock component of the consideration,” Aspen adds: “If answers to these questions are in fact known, the information should be disclosed to Endurance’s own shareholders and the market as a whole.”