The ratings outlook for commercial insurance lines will remain negative in 2013 due to depressed investment yields and sluggish economic growth.This, according to New Jersey-based ratings firm AM Best, which issued its US 2013 outlook for personal and commercial lines this week.“AM Best continues to maintain its negative outlook for the commercial lines segment citing the expectation that continued competitive market conditions, less-favourable loss reserve development, depressed investment yields and sluggish economic growth will lead to more negative rating actions than positive actions in the upcoming year,” the company said in the report.While the negative outlook remains, AM Best believes that commercial insurers will attempt to combat the difficult operating environment through price increases.“However, the level of up pricing will moderate as insurers look to retain business that is otherwise difficult and more costly to attract in today’s challenging business environment,” the company said.Absent a major catastrophic event, the ratings firm believes the commercial sector will remain well-capitalised.“This continues to be true despite a broad attempt by many to manage and deploy capital via stock dividends and share-repurchase activity,” said AM Best.The report states that AM Best continues to maintain a stable outlook for the personal lines segment, driven by auto lines, which continues to record generally adequate performance and stability.On the other hand, personal property lines has posted a volatile weather-driven performance in 2012.“Prior to Superstorm Sandy’s landfall on October 29, 2012, the segment was in line for a significant reduction in overall catastrophe losses in comparison with the devastating impact of frequent weather in 2011,” said AM Best.Despite this trend of frequent and severe events, the personal lines segment remains adequately capitalised. “Given that the auto line represents more than 60 percent of the segment’s net premium written, the outlook remains stable,” the company said.The outlook which implies the majority of this year’s rating actions for the segment is likely to be affirmations.