INVESTMENTS

The following table summarizes, by major security type, the Company's investments as of March 31, 2015 (in thousands):



	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available-for-sale securities:
Short-term investments:
Foreign government securities	$	141,303	$	3	$	(40	)	$	141,266
U.S. government securities	655,798		21		(75		)	655,744
Corporate debt securities	546,066		62		(318		)	545,810
Commercial paper	32,198		—		—			32,198
U.S. government agency securities	4,624		—		(1		)	4,623
Total short-term investments	$	1,379,989	$	86	$	(434	)	$	1,379,641

Long-term investments:
Foreign government securities	$	311,247	$	119	$	(112	)	$	311,254
U.S. government securities	697,558		4,001		(42		)	701,517
Corporate debt securities	3,031,365		12,635		(1,333		)	3,042,667
U.S. government agency securities	2,542		4		—			2,546
U.S. municipal securities	1,106		1		—			1,107
Ctrip corporate debt securities	500,000		—		(17,488		)	482,512
Ctrip equity securities	421,930		10,111		—			432,041
Total long-term investments	$	4,965,748	$	26,871	$	(18,975	)	$	4,973,644

The Company's investment policy seeks to preserve capital and maintain sufficient liquidity to meet operational and other needs of the business. As of March 31, 2015, the weighted-average life of the Company’s U.S. Dollar and Euro fixed income investment portfolios, excluding the Company's fixed income investment in Ctrip, was approximately 1.5 years with an average credit quality of A1/A+.

As of March 31, 2015, foreign government securities included investments in debt securities issued by the governments of the Netherlands, Belgium, France, Austria, the United Kingdom and Sweden.

In August 2014, the Company used its international cash to invest in a five-year Senior Convertible Note issued by Ctrip.com International Ltd. ("Ctrip"). The note was issued at par in an aggregate principal amount of $500 million. Additionally, as of March 31, 2015, the Company had invested $421.9 million of its international cash in Ctrip American Depositary Shares ("ADSs"). The convertible debt and equity securities of Ctrip have been marked to market in accordance with the accounting guidance for available-for-sale securities and at March 31, 2015 show a $17.5 million unrealized loss and $10.1 million unrealized gain, respectively. In connection with the purchase of the convertible note, Ctrip granted the Company the right to appoint an observer to Ctrip's board of directors and permission to acquire Ctrip shares (including through the acquisition of Ctrip ADSs in the open market) over the twelve months following the purchase date, so that combined with ADSs issuable upon conversion of the note, the Company may hold up to 10% of Ctrip's outstanding equity.

The following table summarizes, by major security type, the Company's investments as of December 31, 2014 (in thousands):



	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available-for-sale securities:
Short-term investments:
Foreign government securities	$	52,524	$	—	$	(34	)	$	52,490
U.S. government securities	364,276		24		(34		)	364,266
Corporate debt securities	582,160		15		(652		)	581,523
Commercial paper	39,092		—		—			39,092
U.S. government agency securities	104,829		—		(18		)	104,811
Total short-term investments	$	1,142,881	$	39	$	(738	)	$	1,142,182

Long-term investments:
Foreign government securities	$	12,707	$	—	$	(36	)	$	12,671
U.S. government securities	557,130		80		(762		)	556,448
Corporate debt securities	2,332,030		2,299		(5,296		)	2,329,033
U.S. government agency securities	95,108		97		(111		)	95,094
U.S. municipal securities	1,114		—		(12		)	1,102
Ctrip corporate debt securities	500,000		—		(74,039		)	425,961
Ctrip equity securities	421,930		—		(86,586		)	335,344
Total long-term investments	$	3,920,019	$	2,476	$	(166,842	)	$	3,755,653

The Company has classified its investments as available-for-sale securities. These securities are carried at estimated fair value with the aggregate unrealized gains and losses related to these investments, net of taxes, reflected as a part of "Accumulated other comprehensive loss" in the Unaudited Consolidated Balance Sheets. Classification as short term or long term is based upon the maturity of the debt securities.

The Company recognized $1.8 million of net realized gains related to investments for the three months ended March 31, 2015. There were no realized gains or losses related to investments for the three months ended March 31, 2014.