The businessmen are behind Equisure Inc, an American insurance and metal trading company that has been offering reinsurance to syndicates and insurance companies in the London market and the US since 1995.
The American Stock Exchange suspended trading in Equisure shares on Monday, after questions were raised over the company's accounts and a series of unusual share deals.
Investigations are underway at the American Securities and Exchange Commission and the US Stock Exchange, which has taken the unusual step of hiring accountants to analyse Equisure's financial records.
In a co-ordinated raid, agents for the Stock Exchange turned up at Equisure's offices in London, Belgium and Monaco to recover the company's books.
Equisure, which is unrelated to the well-known Canadian insurance and metal trading company of a similar name, Equisure Financial Network, has more than doubled in value since it began trading on the American Stock Exchange in December after heavy trading by a small group of shareholders. Their identities are hidden behind a series of trust funds and companies registered in the Isle of Man and Monaco. The investigation is focusing on the connections between the shareholders and the company.
The US investigation was sparked when Belgium Police investigating Dai Ichi Kyoto insurance fraud, which cost brokers and insurers in the City of London more than pounds 100m, contacted the US Exchange with concerns over Equisure, which carries out business in Monte Carlo and Antwerp.
Some of Esquire's staff, including one of its accountants have links with Dai Ichi Kyoto which traded on the similarity of its name to a legitimate high-profile Japanese insurance company.
Equisure has hired some well-known figures in the London insurance market as directors. They include Peter Uttley, an activist who campaigned on behalf of the Names who lost money in syndicates run by the Feltrim members' agency and the former Lloyd's broker and insurance consultant Barrie Harding.
Mr Uttley last night denied that the company had been involved in any illegal activity. "The board of directors believe that the suspension was the result of allegations of illegal insider trading activity by affiliates of Equisure including the board of directors. We categorically and emphatically deny the allegations on behalf of ourselves and the company."
"We are working with independent auditors to review all the allegations made against us," he said.