Private equity firm Hellman & Friedman LLC agreed to acquire Hub International Inc., a global insurance broker, in a deal that values the company at about $4.4 billion.

Funds managed by Hellman, co-founded by the late billionaire Warren Hellman, will hold a majority interest in the Chicago company. Hub’s senior management will continue “to have a significant equity position,” the companies said in a joint statement on Monday.

“We have long admired Hub and are delighted to partner with Marty and the entire Hub team,” David Tunnell, managing director of Hellman, said, referring to Hub chairman and CEO Martin Hughes. “Our firm has a long-standing history of investing in insurance businesses and we look forward to working with the company to support its next phase of growth.”

San Francisco-based Hellman has a stake in reinsurer PartnerRe Ltd. (NYSE:PRE) and Sedgwick Claims Management Services Inc. Based on data compiled by Bloomberg, the deal is the largest takeover of a U.S. insurance broker on record. Insurance brokers act as middlemen between insurance buyers and underwriters.

Private equity firms have been investing in insurance services in recent years as they hedge their bets on the steady cash flow and low capital expenditure of the industry. Hub has more than 6,500 employees in the U.S., Canada and Brazil and is forecast to have revenue of $1.2 billion this year.

For the past six years, Hub has been privately held since Apax Partners Holdings Ltd. and Morgan Stanley’s (NYSE:MS) private equity branch bought it for about $1.8 billion, including $145 million of debt, the Chicago Tribune reported.