She noted that 10 or 15 years ago, a deductible of $50,000 to $100,000 limit wasn't unusual. Now, however, those deductibles are $250,000 to $500,000, she said.

"So now you have more companies within the middle-market segment looking for options to the commercial market and how to use a captive to lower their total cost of risk. For us, the group captive is a very important part of the evolution for the middle-market clients," she explained.

Ms. Gray pointed out that captives, traditionally available to Fortune 500 companies, are now accessible to middle-market organizations. The threshold for companies looking at captives has come down every year over the past 10 years.

"Now, even companies with $700,000 in premium spend can be looking at a captive option," Ms. Gray noted.

To streamline the process for its middle-market clients, Aon's group captive solutions practice has collaborated with Zurich in North America, which will issue policies, adjudicate claims and buy reinsurance from a virtual captive that is expected to exist within United SPC, a segregated portfolio company. Through this approach, capital contributions frequently associated with group captives will be eliminated and start-up expenses minimized, the company said.

"Group captives have proven themselves as efficient and stable risk financing mechanisms for decades," Ms. Gray said in a statement. "We view our innovative approach as Group Captives 2.0, building on the past to create the most effective solutions for companies that share our commitment to reducing the total cost of risk."

Aon also announced that Steve Bankes has been tapped to lead Aon's Global Insurance Managers group captive solutions practice as its managing director.

Prior to his appointment, Mr. Bankes was a group captive consultant and held senior positions at two major insurance companies within their alternative market practices.