U.S. commercial insurance prices were more than 4% higher during the third quarter versus prices a year prior, marking the largest overall price shift since 2013, according to a survey by Willis Towers Watson PLC.

Commercial auto, commercial property, excess/umbrella liability, and directors and officers liability all saw significant price increases, while the workers' compensation line experienced price reductions. The changes were more noticeable for large accounts compared with those reported for small and midmarket accounts.

Commercial auto reported price increases were near or above double digits for the eighth straight quarter, and the price changes in most lines accelerated relative to the second quarter.

"[The survey] confirms insurers have been responding to worsening loss trends across affected lines through pricing; other sources suggest terms and conditions have tightened. The question is whether and when workers compensation loss trends will turn, too," said Alejandra Nolibos, Willis Towers Watson's senior director of insurance consulting and technology business.