US property and casualty premium rates grew slightly last month, according to insurance exchange MarketScout.

Rates will rise further if more insurers face deteriorating trading conditions, it says.

“Several medium-sized, publicly traded insurance companies are encountering challenges in their ongoing business operations,” MarketScout CEO Richard Kerr said.

“These companies may be sold, restructured or placed into run-off unless they structure some creative solutions to get them past their current financial crises.”

Property and casualty insurance rates grew 5% last month, commercial property and general liability increased 6% and auto and business owner policies were up 5%.

The lowest increase was in surety at 1%.

 “Jumbo” accounts of more than $US1 million ($1.06 million) premium faced average rate rises of 2%, while small accounts – up to $US25,000 ($26,486) – incurred increases of 6%.

In US personal lines, homeowners’ insurance increased 4%, auto rates were up 4% and insurance for personal articles gained 2%.