Aon Risk Solutions and Berkshire Hathaway International Insurance Ltd. launched an insurance facility Wednesday that offers guaranteed capacity for business where Lloyd's of London underwriters participate.

The facility, which Aon characterizes as an insurance sidecar, is available to Aon clients globally and in most industry segments, said Steve McGill, group president of Aon P.L.C. and chairman and CEO of Aon Risk Solutions.

Sidecars are underwriting vehicles that usually are associated with existing insurers or reinsurers but are separately capitalized. In most cases the sidecars offer reinsurance or retrocessional reinsurance capacity. The Aon/Berkshire Hathaway facility is not separately capitalized but under the terms of the agreement, Berkshire Hathaway will accept 7.5% of Aon retail placements in the London market where there is a Lloyd's participation, Mr. McGill said.

Berkshire Hathaway will follow terms and conditions of the lead underwriter on the underwriting slip. The condition that Lloyd's is involved in the placement “is recognition and respect for Lloyd's technical underwriting expertise,” Mr. McGill said.

The agreement covers most lines of coverage, including property, liability, marine, energy, financial lines and professional lines. Certain space and aviation business is not covered by the agreement. The facility will participate in about 90% of the business Aon places in the London market, Mr. McGill said.

The sidecar will be managed by Aon Underwriting Managers, the London-based brokerage’s managing general agent business, which has been granted authority to bind coverage on behalf of Berkshire Hathaway. The coverage will be available for all business starting March 31.

“Providing highly rated capacity to all our clients is tremendously valuable for them. It gives them a high degree of certainty” in terms of securing capacity and high-quality claims services, Mr. McGill said.

Many large international programs use London to meet their capacity needs and the agreement with Berkshire Hathaway will guarantee a set amount of capacity, he said.

Berkshire Hathaway is rated AA+ by Standard & Poor’s Corp.