US commercial and personal lines rates are hardening, with commercial rates up 5% last month, according to information exchange MarketScout.

It has prompted CEO Richard Kerr to call for an end to aggressive pricing on large accounts.

“Historically, underwriters have been very aggressive in pricing name-brand or large accounts,” he said.

“Other than the cachet or bragging rights, there are few sound underwriting reasons for aggressively pricing large accounts. Risk is risk and exposure is exposure.”

Rates increased 5% last month both for large accounts – paying premium above $US250,000 ($237,700) – and “jumbo” accounts of more than $US1 million ($950,000).

Commercial property, commercial motor and workers’ compensation saw 5% increases, while directors’ and officers’ and professional liability rose 3%.

Home insurance is becoming more expensive as catastrophe modellers widen areas that could be hit by large storms, particularly on coasts, Mr Kerr says.

Homes valued below $US1 million saw a rate increase of 4%, while rates for more expensive homes rose 5% last month. Auto cover rose just 2%.