Mr. Tunnicliffe told National Underwriter that this number is compared with 95 percent of companies in the United Kingdom that own captives and 82 percent of companies in France that own captives.

"Bear in mind, the U.K. only has 38 members in the G500," and France has 38 companies, he added.

Japan, however, has 70 members, but only 23 (33 percent) are captive owners. He noted that one of the interesting findings of the report was the "huge potential" of the "underdeveloped Asian market."

The report found that despite some captive activity in China, none of its 20 G500 companies have a captive. Asian companies that have set up captives may increasingly look to Asian domiciles to establish or relocate their captives, with Hong Kong potentially the main beneficiary as China's economy expands.

The Global 500 group, Mr. Tunnicliffe said, was taken from CNN Money.com. He said the buying group is diverse, with the top company producing revenues of $340 billion, and the number 500 company with revenues of $14 billion.

The report found that mature insurance buyers in certain industries and sectors, thought to have been saturated in captive take-up, actually show relatively substantial growth potential, with about 40 percent of the largest finance and insurance companies not owning a captive at the parent company level.

In manufacturing, according to the report, a third of companies listed in the G500 do not have a captive in place and even mining (including oil and gas extraction), which has the biggest take-up, still has 29 percent of companies without a captive.

Despite reported concerns over the public perception of offshore domiciles and the attention of regulatory and revenue authorities, the report shows that the G500 companies still favor offshore domiciles.

Bermuda is the offshore domicile of choice, accounting for nearly 28 percent of G500 captives, followed by Vermont, Luxembourg, Ireland and Guernsey. These domiciles account for 79 percent of the total captive share of the G500, the study said.

In contrast to conventional wisdom, with steady market growth over the last 20 years, market volatility has had relatively little impact on overall growth patterns, the report found.

There is also a lack of evidence that captives are formed as a reaction to major loss events. The research supports the theory that captives are generally formed for strategic reasons, rather than being driven by a short-term reaction to market volatility.

Stephen Cross, chief executive officer of Aon Captive Services Group, said in a statement, "The research surprised us by highlighting the fact that G500 companies are missing a trick by not taking advantage of the cost and coverage benefits of captives."

He said, "More surprising was the finding that companies in more developed markets, such as the U.S. and Europe, are missing out on these benefits. One of the reasons may be the 'perceived' cost in establishing a globally coordinated approach."

He added, "We expect the G500 to bridge this gap over the next few years, particularly in Asia, where we expect to see significant growth. In addition, there is room for improvement in specific sectors such as financial services and manufacturing."