Mr. Egan resigned as president of Marsh in November after the firm was sued by New York Attorney General Eliot Spitzer over allegations of abuse and fraud related to contingent fee commissions. He was replaced by Mr. Garvey, who served as a co-president until resigning in March for personal reasons.

According to a press release, Integro will be a full-service insurance firm providing dedicated brokerage and risk management services to commercial clients on a global basis.

The firm said it will have executive offices in New York and offices in San Francisco. It intends to be licensed in all fifty states and will be opening offices in Toronto, London, Bermuda and other major U.S. cities in the coming weeks.

The formation of the new firm is in response to the narrowing choice of global brokers, said Mr. Clements in a statement.

"We don't think that's a healthy condition, and furthermore, we don't think this is a zero sum game," he said.

Integro will concentrate on "commercial and institutional enterprises that have large and/or complex risks with specialized insurance needs," the firm said.

It said it is a fresh business model created in the midst of "numerous regulatory investigations," unencumbered by "traditional processes and technology."

Further alluding to the contingency fee scandal, Integro said it would be "free from conflict-of-interest perceptions," putting clients first and practicing transparent business practices.

Andrew J. Barile, an insurance and reinsurance consultant, said it is "a fascinating opportunity" for many in the insurance industry.

He said the $300 million in capital is a significant sum of money for a start-up firm and speculated that the money would be used to attract executives from the major brokerage firms who would bring their customer connections with them.

"The challenge will be to find the producers who can bring the business," said Mr. Barile.

One outgrowth of this could be the start of a bidding war by the major brokerage firms to keep the most successful sales executives in place, he said.

On the prospects of success for the new brokerage firm, he credited Mr. Clements with knowing the business and having a knack for good timing.

"[Mr.] Clements is a pretty savvy guy," Mr. Barile remarked.