FAIR VALUE MEASUREMENTS

Financial assets and liabilities carried at fair value as of December 31, 2017 are classified in the categories described in the tables below (in thousands):



	Level 1		Level 2		Total
ASSETS:
Cash and restricted cash equivalents:
Money market funds	$	1,895,272	$	—	$	1,895,272
U.S. government securities	—		22,265		22,265
Corporate debt securities	—		6,674		6,674
Commercial paper	—		96,321		96,321
Time deposits	17,896		—		17,896
Short-term investments:
International government securities	—		725,376		725,376
U.S. government securities	—		994,118		994,118
Corporate debt securities	—		3,063,315		3,063,315
U.S. government agency securities	—		4,414		4,414
Commercial paper	—		72,650		72,650
Long-term investments:
International government securities	—		607,910		607,910
U.S. government securities	—		834,276		834,276
Corporate debt securities	—		6,656,424		6,656,424
U.S. government agency securities	—		494		494
Ctrip convertible debt securities	—		1,368,500		1,368,500
Ctrip equity securities	953,996		—		953,996
Derivatives:
Currency exchange derivatives	—		1,767		1,767
Total assets at fair value	$	2,867,164	$	14,454,504	$	17,321,668



	Level 1		Level 2		Total
LIABILITIES:
Currency exchange derivatives	$	—	$	127	$	127

Financial assets and liabilities carried at fair value as of December 31, 2016 are classified in the categories described in the tables below (in thousands):



	Level 1		Level 2		Total
ASSETS:
Cash equivalents:
Money market funds	$	977,468	$	—	$	977,468
International government securities	—		30,266		30,266
U.S. government securities	—		176,140		176,140
Corporate debt securities	—		9,273		9,273
Commercial paper	—		1,998		1,998
Time deposits	49,160		—		49,160
Short-term investments:
International government securities	—		249,684		249,684
U.S. government securities	—		456,888		456,888
Corporate debt securities	—		1,510,310		1,510,310
Commercial paper	—		1,998		1,998
Long-term investments:
International government securities	—		659,344		659,344
U.S. government securities	—		766,592		766,592
Corporate debt securities	—		6,001,789		6,001,789
U.S. government agency securities	—		4,952		4,952
Ctrip convertible debt securities	—		1,293,088		1,293,088
Ctrip equity securities	865,302		—		865,302
Derivatives:
Currency exchange derivatives	—		756		756
Total assets at fair value	$	1,891,930	$	11,163,078	$	13,055,008



	Level 1		Level 2		Total
LIABILITIES:
Currency exchange derivatives	$	—	$	1,015	$	1,015

There are three levels of inputs to measure fair value. The definition of each input is described below:


Level 1:	Quoted prices in active markets that are accessible by the Company at the measurement date for identical assets and liabilities.


Level 2:	Inputs that are observable, either directly or indirectly. Such prices may be based upon quoted prices for identical or comparable securities in active markets or inputs not quoted on active markets, but corroborated by market data.


Level 3:	Unobservable inputs are used when little or no market data is available.

Investments in corporate debt securities, U.S. and international government securities, commercial paper, government agency securities and convertible debt securities are considered "Level 2" valuations because the Company has access to quoted prices, but does not have visibility to the volume and frequency of trading for all of these investments. For the Company's investments, a market approach is used for recurring fair value measurements and the valuation techniques use inputs that are observable, or can be corroborated by observable data, in an active marketplace.

The Company's derivative instruments are valued using pricing models. Pricing models take into account the contract terms as well as multiple inputs where applicable, such as interest rate yield curves, option volatility and currency rates. Derivatives are considered "Level 2" fair value measurements. The Company's derivative instruments are typically short-term in nature.

As of December 31, 2017 and 2016, the Company's cash consisted of bank deposits. Other financial assets and liabilities, including restricted cash and cash equivalents, accounts receivable, accounts payable, accrued expenses and deferred merchant bookings are carried at cost which approximates their fair value because of the short-term nature of these items. As of December 31, 2017 and 2016, the Company held investments in equity securities of private companies of approximately $450.9 million and $7.6 million, respectively, and these investments are accounted for under the cost method of accounting (see Note 4). See Note 4 for information on the carrying value of available-for-sale investments, Note 10 for the estimated fair value of the Company's outstanding Senior Notes and Note 18 for the Company's contingent liabilities associated with business acquisitions.

In the normal course of business, the Company is exposed to the impact of foreign currency fluctuations. The Company limits these risks by following established risk management policies and procedures, including the use of derivatives. See Note 2 for the Company's accounting policy on derivative financial instruments.

Derivatives Not Designated as Hedging Instruments — The Company is exposed to adverse movements in currency exchange rates as the operating results of its international operations are translated from local currency into U.S. Dollars upon consolidation. The Company enters into average-rate derivative contracts to hedge translation risks from short-term foreign exchange rate fluctuations for the Euro, British Pound Sterling and certain other currencies versus the U.S. Dollar. As of December 31, 2017 and 2016, there were no outstanding derivative contracts related to foreign currency translation risks. Derivatives associated with these translation risks resulted in foreign currency losses of $2.8 million for the year ended December 31, 2017, foreign currency gains of $3.4 million for the year ended December 31, 2016 and foreign currency losses of $6.6 million for the year ended December 31, 2015, which were recorded in "Foreign currency transactions and other" in the Consolidated Statements of Operations.

The Company also enters into foreign currency forward contracts to hedge its exposure to the impact of movements in currency exchange rates on its transactional balances denominated in currencies other than the functional currency. Foreign currency derivatives outstanding as of December 31, 2017 associated with foreign currency transaction risks resulted in a net asset of $1.6 million, with an asset in the amount of $1.7 million recorded in "Prepaid expenses and other current assets" and a liability in the amount of $0.1 million recorded in "Accrued expenses and other current liabilities" in the Consolidated Balance Sheet. Foreign currency derivatives outstanding as of December 31, 2016 associated with foreign currency transaction risks resulted in a net liability of $0.3 million, with a liability in the amount of $1.0 million recorded in "Accrued expenses and other current liabilities" and an asset in the amount of $0.7 million recorded in "Prepaid expenses and other current assets" in the Consolidated Balance Sheet. Derivatives associated with these transaction risks resulted in foreign currency gains of $45.4 million and foreign currency losses of $15.8 million and $15.3 million for the years ended December 31, 2017, 2016 and 2015, respectively. These mark-to-market adjustments on the derivative contracts, offset by the effect of changes in currency exchange rates on transactions denominated in currencies other than the functional currency, resulted in net losses of $27.2 million, $13.9 million and $13.8 million for the years ended December 31, 2017, 2016 and 2015, respectively. These net impacts are reported in "Foreign currency transactions and other" in the Consolidated Statements of Operations.

The settlement of derivative contracts not designated as hedging instruments resulted in net cash inflows of $41.2 million and $4.5 million for the years ended December 31, 2017 and 2016, respectively, compared to a net cash outflow of $33.9 million for the year ended December 31, 2015, and are reported within "Net cash provided by operating activities" in the Consolidated Statements of Cash Flows.

Derivatives Designated as Hedging Instruments — The Company had no foreign currency forward contracts designated as hedges of its net investment in a foreign subsidiary during the years ended December 31, 2017 and 2016. A net cash inflow of $5.2 million for the year ended December 31, 2015 was reported within "Net cash used in investing activities" in the Consolidated Statement of Cash Flows.

Embedded Derivative — In September 2016, the Company invested $25 million in a Ctrip convertible note (see Note 4). The Company determined that the conversion option for this note met the definition of an embedded derivative. At December 31, 2017 and 2016, the embedded derivative had an estimated fair value of $1.8 million and is reported in the Consolidated Balance Sheets with its host contract in "Long-term investments." The embedded derivative is bifurcated for measurement purposes only and the mark-to-market for the year ended December 31, 2016 was a loss of $1.1 million, which is included in "Foreign currency transactions and other" in the Company's Consolidated Statement of Operations.