As noted above, our excess of loss property contracts generally cover all natural perils, and our predominant exposure under such coverage is to property damage. However, other risks, including business interruption and other non-property losses, may also be covered under our property reinsurance contracts when arising from a covered peril. We offer our coverages on a worldwide basis. Because of the wide range of possible catastrophic events to which we are exposed, including the size of such events and the potential for multiple events to occur in the same time period, our property business is volatile and our financial condition and results of operations reflect this volatility. To moderate the volatility of our risk portfolio, we may increase or decrease our presence in the property business based on market conditions and our assessment of risk-adjusted pricing adequacy. We frequently purchase reinsurance or other protection for our own account for a number of reasons, including to optimize the expected outcome of our underwriting portfolio, to manage capital requirements for regulated entities and to reduce the financial impact that a large catastrophe or a series of catastrophes could have on our results. Casualty and Specialty Segment We write casualty and specialty reinsurance and insurance covering primarily targeted classes of business where we believe we have a sound basis for underwriting and pricing the risk we assume. This business is predominantly reinsurance, however our book of insurance business has been increasing in recent periods, and may continue to do so. The following table shows gross premiums written in our Casualty and Specialty segment aggregated by class of business: Year ended December 31, 2021 2020 2019 (in thousands, except percentages) Gross Premiums Written Percentage of Gross Premiums Written Gross Premiums Written Percentage of Gross Premiums Written Gross Premiums Written Percentage of Gross Premiums Written General casualty (1) $ 1,258,536 32.5 % $ 904,594 32.2 % $ 807,901 34.0 % Professional liability (2) 1,283,864 33.1 % 836,120 29.8 % 650,750 27.4 % Financial lines (3) 498,946 12.9 % 514,192 18.3 % 457,000 19.2 % Other (4) 833,728 21.5 % 552,117 19.7 % 461,114 19.4 % Total Casualty and Specialty segment gross premiums written $ 3,875,074 100.0 % $ 2,807,023 100.0 % $ 2,376,765 100.0 % (1) Includes automobile liability, casualty clash, employer’s liability, umbrella or excess casualty, workers’ compensation and general liability. (2) Includes directors and officers, medical malpractice, and professional indemnity. (3) Includes financial guaranty, mortgage guaranty, political risk, surety and trade credit. (4) Includes accident and health, agriculture, aviation, cyber, energy, marine, satellite and terrorism. Lines of business such as regional multi-line and whole account may have characteristics of various other classes of business, and are allocated accordingly. In recent years, we have expanded our Casualty and Specialty segment operations through organic growth initiatives and acquisitions, and we plan to continue to expand these operations over time if market conditions are appropriate. Our Casualty and Specialty segment gross premiums written may be subject to significant volatility as certain lines of business in this segment can be influenced by a small number of relatively large transactions. We seek to underwrite these lines using a disciplined underwriting approach and sophisticated analytical tools. We generally target lines of business where we believe we can adequately quantify the risks assumed and provide coverage where we believe our underwriting is robust and the market is attractive. We also seek to identify market dislocations and write new lines of business whose risk and return characteristics are estimated to exceed our hurdle rates. Furthermore, we also seek to manage the correlations of this business with our overall portfolio. We believe that our underwriting and analytical capabilities have positioned us well to manage our casualty and specialty business. We offer our casualty and specialty reinsurance products principally on a proportional basis, and we also provide excess of loss coverage. These products frequently include tailored features such as limits or sub- limits which we believe help us manage our exposures. Any liability exceeding, or otherwise not subject to, 7