With insurer ACE recently acquiring Chubb for more than $28 billion, we decided to check Quant Ratings for other property and casualty insurance companies to buy. The insurance industry contributes 4.5% of GDP, of which 74% is provided by insurance carriers that underwrite insurance, and 26% by insurance agencies that sell insurance to the public. The sector has grown faster than GDP in the last 17 years, and the price increases have grown less than inflation, which is an indication that the business is very competitive. Here are some of the best property and casualty insurance companies TheStreet Quant Ratings says you should consider looking at. Number 3 is Hanover Insurance Group. With an 'A+' rating, the company's strengths can be seen in its revenue growth and increase in net income. 2nd is Aspen Insurance Holdings Limited. This rating is also an 'A+.' Aspen Insurance Holdings thrives in its solid stock price performance and increase in net income. Number 1 is Arch Capital Group. This too has an 'A+' rating. The company flourishes in its revenue growth and notable return on equity. TheStreet Ratings are algorithmic stock picks based on 32 major data points. S&P 500 stocks rated 'buy' yielded a 16-and-a-half-percent return in 2014, beating the S&P 500 Total Return Index by more than 300 basis points. For the full reports on these stocks, you can check out TheStreet.com/QuantRatings.