15. SEGMENT REPORTING

The U.S. Reinsurance operation writes property and casualty reinsurance and specialty lines of business, including Marine, Aviation, Surety and Accident and Health ("A&H") business, on both a treaty and facultative basis, through reinsurance brokers, as well as directly with ceding companies primarily within the U.S. The International operation writes non-U.S. property and casualty reinsurance through Everest Re's branches in Canada and Singapore and through offices in Brazil, Miami and New Jersey. The Bermuda operation provides reinsurance and insurance to worldwide property and casualty markets through brokers and directly with ceding companies from its Bermuda office and reinsurance to the United Kingdom and European markets through its UK branch and Ireland Re. The Insurance operation writes property and casualty insurance directly and through brokers, surplus lines brokers and general agents within the U.S., Canada and Europe.

These segments are managed independently, but conform with corporate guidelines with respect to pricing, risk management, control of aggregate catastrophe exposures, capital, investments and support operations. Management generally monitors and evaluates the financial performance of these operating segments based upon their underwriting results.

Underwriting results include earned premium less losses and loss adjustment expenses ("LAE") incurred, commission and brokerage expenses and other underwriting expenses. We measure our underwriting results using ratios, in particular loss, commission and brokerage and other underwriting expense ratios, which, respectively, divide incurred losses, commissions and brokerage and other underwriting expenses by premiums earned.

For inter-affiliate reinsurance and business written through the Lloyd's Syndicate, business is generally reported within the segment in which the business was first produced, consistent with how the business is managed.

The Company does not maintain separate balance sheet data for its operating segments. Accordingly, the Company does not review and evaluate the financial results of its operating segments based upon balance sheet data.

The following tables present the underwriting results for the operating segments for the periods indicated:


	Three Months Ended
U.S. Reinsurance	March 31,
(Dollars in thousands)	2019		2018
Gross written premiums	$	764,146	$	644,222
Net written premiums		669,707		545,831

Premiums earned	$	626,471	$	563,385
Incurred losses and LAE		320,104		545,193
Commission and brokerage		167,102		127,320
Other underwriting expenses		15,591		16,886
Underwriting gain (loss)	$	123,674	$	(126,014	)


	Three Months Ended
International	March 31,
(Dollars in thousands)	2019		2018
Gross written premiums	$	400,054	$	366,724
Net written premiums		375,505		345,155

Premiums earned	$	350,935	$	343,604
Incurred losses and LAE		254,135		127,024
Commission and brokerage		81,425		82,177
Other underwriting expenses		8,681		10,576
Underwriting gain (loss)	$	6,694	$	123,827


	Three Months Ended
Bermuda	March 31,
(Dollars in thousands)	2019		2018
Gross written premiums	$	367,851	$	415,686
Net written premiums		349,341		394,968

Premiums earned	$	330,113	$	319,134
Incurred losses and LAE		197,959		129,513
Commission and brokerage		74,110		81,487
Other underwriting expenses		11,497		10,133
Underwriting gain (loss)	$	46,547	$	98,001


	Three Months Ended
Insurance	March 31,
(Dollars in thousands)	2019		2018
Gross written premiums	$	595,057	$	504,975
Net written premiums		457,145		386,252

Premiums earned	$	425,178	$	393,304
Incurred losses and LAE		276,352		255,447
Commission and brokerage		66,837		66,655
Other underwriting expenses		63,216		58,689
Underwriting gain (loss)	$	18,773	$	12,513

The following table reconciles the underwriting results for the operating segments to income before taxes as reported in the consolidated statements of operations and comprehensive income (loss) for the periods indicated:


	Three Months Ended
	March 31,
(Dollars in thousands)	2019			2018
Underwriting gain (loss)	$	195,688		$	108,327
Net investment income		140,976			138,294
Net realized capital gains (losses)		92,232			(24,901	)
Net derivative gain (loss)		3,231			273
Corporate expenses		(6,652	)		(8,996	)
Interest, fee and bond issue cost amortization expense		(7,631	)		(7,418	)
Other income (expense)		(9,053	)		12,064
Income (loss) before taxes	$	408,791		$	217,643

The Company produces business in the U.S., Bermuda and internationally. The net income deriving from and assets residing in the individual foreign countries in which the Company writes business are not identifiable in the Company's financial records. Based on gross written premium, the table below presents the largest country, other than the U.S., in which the Company writes business, for the periods indicated:


	Three Months Ended
	March 31,
(Dollars in thousands)	2019		2018
United Kingdom gross written premium	$	263,857	$	258,259

No other country represented more than 5% of the Company's revenues.