Growth in US commercial rate slowed to 2% last month, compared with 3% in May, according to analyst MarketScout.

“The commercial market continues to adjust downward as a result of improved underwriting results and an abundance of capacity,” CEO Richard Kerr said.

By class, premiums for commercial property, general liability, commercial auto and business owner policy all grew 3% last month.

Workers’ compensation rates increased 1%, compared with 3% in May.

Rate rises on small and medium accounts, worth $US25,000 to $US250,000 ($26,611 to $266,157), held steady at more than 3%, while rises for accounts of $US250,001 to $US1 million ($1.064 million) slowed to 1% compared with 2% in May.

Rates on accounts of more than $US1 million were flat in June for the first time since the market turned towards rate increases in November 2011.

“It’s not surprising the jumbo accounts have gone flat because the name-brand account continues to allure underwriters, despite the lower return on equity,” Mr Kerr said.

“There is a pricing benefit to being a name-brand, Fortune 1000 insurance buyer.”

In personal lines, homeowner insurance rates grew 4% in June and motor insurance gained 4%.