The operating results of the property and casualty insurance and reinsurance industry are subject to significant fluctuations due to competition, catastrophic events, general economic conditions, interest rates and other factors, such as changes in tax laws and regulations. The operating results of SCOR U.S. historically have been influenced by these cycles. In recent years, the results of certain casualty lines of business have become less predictable for some insurers and reinsurers as a result of expanding theories of tort and insurance liability and latent risks, such as asbestos and pollution liability whose effects may not be known for many years. The operating subsidiaries of SCOR U.S. have not underwritten significant amounts of business in those classes or with those insurers that are known to be exposed to asbestos and environmental related claims. The Company has not experienced any material amount of net loss reporting or development on claims related to these exposures. In addition, the Company is significantly protected from certain adverse loss reserve development through retrocessional agreements with SCOR S.A., its majority shareholder (see Note 4 to the Company's Consolidated Financial Statements). Any recoveries under such agreements are considered to be fully realizable. Based on the above information, the Company believes that its exposure to asbestos and environmental related claims is not material to the Company's financial position or results of operations.
Gross premiums written for 1994 decreased 8% to $306.8 million from $334.5 million in 1993. Net premiums written for 1994 decreased 6% to $231.1 million from $245.4 million for 1993. Gross premiums written and net premiums written for 1994 were increased by $1.0 million and reduced by $5.0 million, respectively, for additional premiums to reinstate catastrophe reinsurance protections primarily related to the Northridge earthquake. Excluding these reinstatement premiums, gross premiums written and net premiums written for 1994 decreased by 9% and 4%, respectively, compared with 1993. The decrease in premium volume was attributable principally to the Company's continued withdrawal from certain property and casualty lines of business where the Company believes rates and/or conditions are inadequate. More specifically, throughout 1994 the Company has been reducing its property business written on a pro rata basis. A combination of an acceleration in the reduction of this business and fewer attractive opportunities in targeted lines of business caused the reduction in 1994 premium volume. In general, a weak pricing environment persisted throughout 1994, with the exception of catastrophe-exposed risks and some specialized lines of business.
Commission expenses decreased 3% to $59.4 million in 1994 from $61.3 million in 1993. The decrease was caused principally by the decline in the Company's net premium volume. The commission ratio was 26.0% for 1994 and 1993. The effect of net reinstatement premiums related primarily to the Northridge earthquake added approximately 0.5 points to the 1994 commission ratio.
Statements, the Company has made various acquisitions. The pre-tax effect on operations from recent acquisitions, including the amortization of goodwill and acquired licenses, was a charge of $2.8 million in 1994 compared with a charge of $2.6 million in 1993. The operations of the acquired companies are not expected to have a material effect on the Company's liquidity, financial position or results of operations.
The combined ratio was 105.1% for 1993, compared with 127.4% for 1992. The effect of property catastrophe events on the 1993 and 1992 combined ratio was 5.8 points and 29.8 points, respectively.