27 Gross Premiums Written. Gross premiums written for the year ended December 31, 2004 increased by $0.1 billion, or 3.8%, to $2.7 billion from $2.6 billion for the year ended December 31, 2003. The increase in premium volume is attributable to increases in the EuroAsia division of $145.6 million, or 35.7%, the London Market division of $9.8 million, or 2.2%, and the U.S. Insurance division of $78.2 million, or 23.5%. These increases are offset by a decrease in the Americas division of $158.2 million, or 11.1%. Year Ended December 31, 2004 Compared to Year Ended December 31, 2003 Results of Operations Other underwriting expenses consist of cost of operations associated with our underwriting activities. These expenses include compensation, rent, and all other general expenses allocated to our underwriting activity and exclude any investment or claims related expenses. Acquisition costs consist principally of commissions and brokerage expenses incurred on business written under reinsurance contracts or certificates and insurance policies. These costs ar e deferred and amortized over the period in which the related premiums are earned. Commission adjustments with ceding companies are accrued based on the underwriting profitability of the business produced. Deferred acquisition costs ar limited to their estimated realizable value, which considers anticipated losses and loss adjustment expenses and estimated remaining costs of servicing the contracts or certificates, all based on our historical experience. The methods of making such estimates and establishing the deferred costs are continually reviewed by the Company, and any adjustments ar made in the accounting period in which the adjustment arose. We believe the estimate of these deferred acquisition costs is a “critical accounting estimate,” because changes in these estimates can materially affect net income. The U.S. Insurance division accounted for $344.1 million of our gr oss reserves for unpaid losses and loss adjustment expenses, comprised of case reserves of $86.2 million and IBNR of $257.9 million as of December 31, 2004. The U.S. Insurance division ceded reserves for losses and loss adjustment expenses of $144.6 million, of which $105.4 million is IBNR as of December 31, 2004. U.S. Insurance division net reserves for unpaid losses and loss adjustment expenses as of December 31, 2004 were $199.5 million, of which $47.0 million was case reserves and $152.5 million was IBNR. The London Market division accounted for $778.1 million of our gr oss reserves for unpaid losses and loss adjustment expenses, comprised of case reserves of $239.6 million and IBNR of $538.5 million as of December 31, 2004. The London Market division ceded reserves for losses and loss adjustment expenses of $188.9 million, of which $132.8 million is IBNR as of December 31, 2004. London Market division net reserves for unpaid losses and loss adjustment expenses as of December 31, 2004 were $589.1 million of which $183.4 million was case reserves and $405.7 million was IBNR. The EuroAsia division accounted for $375.4 million of our gross r eserves for unpaid losses and loss adjustment expenses, comprised of case reserves of $177.4 million and IBNR of $198.0 million as of December 31, 2004. The EuroAsia division ceded reserves for losses and loss adjustment expenses of $6.2 million, of which $1.7 million is IBNR as of December 31, 2004. EuroAsia division net reserves for unpaid losses and loss adjustment expenses as of December 31, 2004 were $369.2 million, of which $172.9 million was case reserves and $196.3 million was IBNR. The Americas division accounted for $2.7 billion of our gross r eserves for unpaid losses and loss adjustment expenses, comprised of case reserves of $1.6 billion and IBNR of $1.1 billion as of December 31, 2004. The Americas division ceded reserves for losses and loss adjustment expenses of $752.3 million, of which $229.9 million is IBNR as of December 31, 2004. The Americas division net reserves for unpaid losses and loss adjustment expenses as of December 31, 2004 were $2.0 billion of which $1.1 billion was case reserves and $849.9 million was IBNR. expenses for asbestos and environmental claims wer $50.7 million and $10.9 million, respectively, as of December 31, 2004 (see note 16 to the consolidated financial statements). As of December 31, 2004, we had gross reserves for unpaid losses and loss adjustment expenses of $4.2 billion, comprised of reported case loss reserves (“case reserves”) of $2.2 billion and incurred but not reported reserves (“IBNR”) of $2.0 billion. We had ceded reserves for unpaid losses and loss adjustment expenses of $1.1 billion, of which $469.8 million was IBNR. Net reserves for unpaid losses and loss adjustment expenses as of December 31, 2004 were $3.1 billion, of which $1.5 billion was case reserves and $1.6 billion was IBNR.