Item 7A. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK - Continued

Restricted Cash and Marketable Investment Securities and Other Investments

Restricted Cash and Marketable Investment Securities

As of December 31, 2015, we had $21.0 million of restricted cash and marketable investment securities invested in: (a) cash; (b) debt instruments of the U.S. government and its agencies; (c) commercial paper and corporate notes with an overall average maturity of less than one year and rated in one of the four highest rating categories by at least two nationally recognized statistical rating organizations; and (d) instruments with similar risk, duration and credit quality characteristics to the commercial paper described above. Based on our investment portfolio as of December 31, 2015, a hypothetical 10% increase in average interest rates would not have a material impact on the fair value of our restricted cash and marketable investment securities.

Investments in Unconsolidated Entities

As of December 31, 2015, we had $209.3 million of noncurrent equity instruments that we hold for strategic business purposes and account for under the cost or equity methods of accounting. The fair value of these instruments is not readily determinable. We periodically review these investments and estimate fair value when there are indications of impairment. A hypothetical 10% adverse change in the value of these debt and equity instruments would result in a decrease of approximately $20.9 million in the value of these investments.

Our ability to realize value from our strategic investments in companies that are not publicly traded depends on the success of those companies’ businesses and their ability to obtain sufficient capital to execute their business plans. Because private markets are not as liquid as public markets, there is also increased risk that we will not be able to sell these investments, or that when we desire to sell them we will not be able to obtain fair value for them.

Foreign Currency Exchange Risk

We generally conduct our business in U.S. dollars. Our international business is conducted in a variety of foreign currencies with our largest exposures being to the Brazilian real, the Indian rupee, and the British pound. This exposes us to fluctuations in foreign currency exchange rates. Transactions in foreign currencies are converted into U.S. dollars using exchange rates in effect on the dates of the transactions.

Our objective in managing our exposure to foreign currency changes is to reduce earnings and cash flow volatility associated with foreign exchange rate fluctuations. Accordingly, we may enter into foreign exchange contracts to mitigate risks associated with foreign currency denominated assets, liabilities, commitments and anticipated foreign currency transactions. As of December 31, 2015, we had $5.3 million of net foreign currency denominated receivables and payables outstanding, and foreign currency forward contracts with a notional value of $2.6 million in place to partially mitigate foreign currency exchange risk. The estimated fair values of the foreign exchange contracts were not material as of December 31, 2015. The impact of a hypothetical 10% adverse change in exchange rates on the carrying amount of the net assets and liabilities of our foreign subsidiaries would be an estimated loss of $22.7 million as of December 31, 2015.

Derivative Financial Instruments

We generally do not use derivative financial instruments for speculative purposes and we generally do not apply hedge accounting treatment to our derivative financial instruments. We evaluate our derivative financial instruments from time to time but there can be no assurance that we will not enter into additional foreign currency forward contracts, or take other measures, in the future to mitigate our foreign exchange risk.