Civil unrest in Hong Kong and Chile, together with tornadoes and wildfires in the US, and a typhoon in Japan, contributed to estimated net pre-tax catastrophe losses of $430 million for Chubb Ltd in the fourth quarter.After tax, the estimated catastrophe losses total $353 million. The company said the losses were primarily attributable to severe weather-related events around the world.The estimates are net of reinsurance, include reinstatement premiums and comprise losses generated from the company’s commercial and personal property and casualty insurance businesses as well as its reinsurance operations globally.In addition, for North America agricultural insurance, the company estimates for the fourth quarter an underwriting loss of $23 million pre-tax, or $18 million after tax, primarily attributable to crop yield shortfalls resulting from poor growing conditions. In the third quarter of 2019, the insurer and reinsurer recognised a charge related to preventive planting claims due to the impact of wet weather conditions. For agriculture, the combined ratios for the fourth quarter and full-year 2019 are expected to be 105.4 per cent and 95.1 per cent, respectively.Chubb expects to issue its fourth quarter earnings release after the markets close on February 4.