U.S. commercial casualty insurance rates appear likely to follow those of commercial property by softening in 2015, according to a report released Monday by Marsh L.L.C.

Marsh's “United States Insurance Market Report 2015” notes that casualty rates edged up slightly in 2014, but the rate of increased rates slowed. One potential issue for general liability policyholders is cyber risk, according to the report.

Policyholders “will continue to face cyber risk challenges stemming from a 2014 decision by the Insurance Services Office,” said Marsh. “ISO contends that damages related to data breaches and certain data-related liabilities are not intended to be covered under GL policies, and should be addressed through dedicated cyber insurance policies.”

Marsh noted that cyber coverage remains one of the fastest growing sectors in the insurance market, with continued growth in premium and policy count, as well as the “steady influx” of new capacity. “Continued growth in supply and demand for cyber insurance, coupled with unexpected loss activity, led to significant volatility in pricing during 2014, which is likely to continue in 2015,” said Marsh.

Marsh said that strong competition generally prevented large rate changes for umbrella and excess liability. In fact, “most insureds renewed in the fourth quarter with rate decreases,” said Marsh. The report added, though, that insurers are exercising greater discipline and requiring more detailed underwriting submissions.

The property market softened in 2014 and is likely to continue doing so in 2015, the Marsh report said.

As this year began, Marsh said that the property insurance market “was significantly oversupplied with capacity, including from alternative capital flowing into the reinsurance market from non-traditional sources such as hedge funds, pension funds, and other institutional investors.” The report noted that such a situation usually encourages competition among insurers and “favorable rates for insureds.”