DEBT

Revolving Credit Facility

In October 2011, the Company entered into a $1.0 billion five-year unsecured revolving credit facility with a group of lenders. Borrowings under the revolving credit facility will bear interest, at the Company's option, at a rate per annum equal to either (i) the adjusted LIBOR for the interest period in effect for such borrowing plus an applicable margin ranging from 1.00% to 1.50%; or (ii) the greatest of (a) JPMorgan Chase Bank, National Association's prime lending rate, (b) the federal funds rate plus 0.50%, and (c) an adjusted LIBOR for an interest period of one month plus 1.00%, plus an applicable margin ranging from 0.00% to 0.50%. Undrawn balances available under the revolving credit facility are subject to commitment fees at the applicable rate ranging from 0.10% to 0.25%.

The revolving credit facility provides for the issuance of up to $100.0 million of letters of credit as well as borrowings of up to $50.0 million on same-day notice, referred to as swingline loans. Borrowings under the revolving credit facility may be made in U.S. Dollars, Euros, British Pounds Sterling and any other foreign currency agreed to by the lenders. The proceeds of loans made under the facility will be used for working capital and general corporate purposes. As of September 30, 2013 and December 31, 2012, there were no borrowings under the facility and there were approximately $1.9 million of letters of credit issued under the facility for both periods.

Convertible Debt

Convertible debt as of September 30, 2013 consisted of the following (in thousands):



September 30, 2013	Outstanding Principal Amount		Unamortized Debt Discount			Carrying Value
1.25% Convertible Senior Notes due March 2015	$	574,996	$	(36,730	)	$	538,266
1.0% Convertible Senior Notes due March 2018	1,000,000		(102,168		)	897,832
0.35% Convertible Senior Notes due June 2020	1,000,000		(166,805		)	833,195
Outstanding convertible debt	$	2,574,996	$	(305,703	)	$	2,269,293

Convertible debt as of December 31, 2012 consisted of the following (in thousands):



December 31, 2012	Outstanding Principal Amount		Unamortized Debt Discount			Carrying Value
1.25% Convertible Senior Notes due March 2015	$	574,999	$	(54,655	)	$	520,344
1.0% Convertible Senior Notes due March 2018	1,000,000		(118,004		)	881,996
Outstanding convertible debt	$	1,574,999	$	(172,659	)	$	1,402,340

Based upon the closing price of the Company's common stock for the prescribed measurement period during the three months ended September 30, 2013 and December 31, 2012, the contingent conversion threshold on the 2015 Notes (as defined below) was exceeded. Therefore, the 2015 Notes were convertible at the option of the holders. Accordingly, the Company reported the carrying value of the 2015 Notes as a current liability as of September 30, 2013 and December 31, 2012. Since these notes are convertible at the option of the holders and the principal amount is required to be paid in cash, the difference between the principal amount and the carrying value is reflected as convertible debt in the mezzanine section on the Company's Unaudited Consolidated Balance Sheets. Therefore, with respect to the 2015 Notes, the Company reclassified $36.7 million and $54.7 million before tax from additional paid-in capital to convertible debt in the mezzanine section on the Company's Unaudited Consolidated Balance Sheets as of September 30, 2013 and December 31, 2012, respectively. The determination of whether or not the 2015 Notes are convertible must continue to be performed on a quarterly basis. Consequently, the 2015 Notes may not be convertible in future quarters, and therefore may again be classified as long-term debt, if the contingent conversion threshold is not met in such quarters. As of October 25, 2013, the Company had received early conversion notices for an aggregate principal amount of approximately $390 million associated with the 1.25% Convertible Senior Notes due March 2015. During the three months ended December 31, 2013, the Company will deliver cash of approximately $390 million to satisfy the aggregate principal amount and will issue shares of its common stock in satisfaction of the conversion value in excess of the principal amount for the convertible debt that was converted prior to maturity.

The contingent conversion thresholds on the 2018 Notes (as defined below) and the 2020 Notes (as defined below) were not exceeded at September 30, 2013 and the contingent conversion threshold for the 2018 Notes was not exceeded at December 31, 2012, and therefore these Notes are reported as a non-current liability on the Unaudited Consolidated Balance Sheets.

As of September 30, 2013 and December 31, 2012, the estimated market value of the outstanding convertible senior notes was approximately $4.3 billion and $2.3 billion, respectively, and was considered a "Level 2" fair value measurement (see Note 5). Fair value was estimated based upon actual trades at the end of the reporting period or the most recent trade available as well as the Company's stock price at the end of the reporting period. A substantial portion of the market value of the Company's debt in excess of the outstanding principal amount relates to the conversion premium on the convertible senior notes.

Description of Senior Notes

In May 2013, the Company issued in a private placement $1.0 billion aggregate principal amount of Convertible Senior Notes due June 15, 2020, with an interest rate of 0.35% (the "2020 Notes"). The 2020 Notes were issued with an initial discount of $20.0 million. The Company paid $0.9 million in debt issuance costs during the nine months ended September 30, 2013, related to this offering. The 2020 Notes are convertible, subject to certain conditions, into the Company's common stock at a conversion price of approximately $1,315.10 per share. The 2020 Notes are convertible, at the option of the holder, prior to June 15, 2020, upon the occurrence of specific events, including but not limited to a change in control, or if the closing sales price of the Company's common stock for at least 20 trading days in the period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is more than 150% of the applicable conversion price in effect for the notes on the last trading day of the immediately preceding quarter. In the event that all or substantially all of the Company's common stock is acquired on or prior to the maturity of the 2020 Notes in a transaction in which the consideration paid to holders of the Company's common stock consists of all or substantially all cash, the Company would be required to make additional payments in the form of additional shares of common stock to the holders of the 2020 Notes in an aggregate value ranging from $0 to approximately $397.0 million depending upon the date of the transaction and the then current stock price of the Company. As of March 15, 2020, holders will have the right to convert all or any portion of the 2020 Notes. The 2020 Notes may not be redeemed by the Company prior to maturity. The holders may require the Company to repurchase the 2020 Notes for cash in certain circumstances. Interest on the 2020 Notes is payable on June 15 and December 15 of each year.

In March 2012, the Company issued in a private placement $1.0 billion aggregate principal amount of Convertible Senior Notes due March 15, 2018, with an interest rate of 1.0% (the "2018 Notes"). The Company paid $20.9 million in debt issuance costs during the nine months ended September 30, 2012, related to this offering. The 2018 Notes are convertible, subject to certain conditions, into the Company's common stock at a conversion price of approximately $944.61 per share. The 2018 Notes are convertible, at the option of the holder, prior to March 15, 2018, upon the occurrence of specific events, including but not limited to a change in control, or if the closing sales price of the Company's common stock for at least 20 trading days in the period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is more than 150% of the applicable conversion price in effect for the notes on the last trading day of the immediately preceding quarter. In the event that all or substantially all of the Company's common stock is acquired on or prior to the maturity of the 2018 Notes in a transaction in which the consideration paid to holders of the Company's common stock consists of all or substantially all cash, the Company would be required to make additional payments in the form of additional shares of common stock to the holders of the 2018 Notes in aggregate value ranging from $0 to approximately $344.0 million depending upon the date of the transaction and the then current stock price of the Company. As of December 15, 2017, holders will have the right to convert all or any portion of the 2018 Notes. The 2018 Notes may not be redeemed by the Company prior to maturity. The holders may require the Company to repurchase the 2018 Notes for cash in certain circumstances. Interest on the 2018 Notes is payable on March 15 and September 15 of each year.

In March 2010, the Company issued in a private placement $575.0 million aggregate principal amount of Convertible Senior Notes due March 15, 2015, with an interest rate of 1.25% (the "2015 Notes"). The Company paid $13.3 million in debt issuance costs associated with the 2015 Notes for the year ended December 31, 2010. The 2015 Notes are convertible, subject to certain conditions, into the Company's common stock at a conversion price of approximately $303.06 per share. The 2015 Notes are convertible, at the option of the holder, prior to March 15, 2015 upon the occurrence of specified events, including, but not limited to a change in control, or if the closing sales price of the Company's common stock for at least 20 trading days in the period of the 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is more than 150% of the applicable conversion price in effect for the notes on the last trading day of the immediately preceding quarter. In the event that all or substantially all of the Company's common stock is acquired on or prior to the maturity of the 2015 Notes in a transaction in which the consideration paid to holders of the Company's common stock consists of all or substantially all cash, the Company would be required to make additional payments in the form of additional shares of common stock to the holders of the 2015 Notes in aggregate value ranging from $0 to approximately $132.7 million depending upon the date of the transaction and the then current stock price of the Company. As of December 15, 2014, holders will have the right to convert all or any portion of the 2015 Notes. The 2015 Notes may not be redeemed by the Company prior to maturity. The holders may require the Company to repurchase the 2015 Notes for cash in certain circumstances. Interest on the 2015 Notes is payable on March 15 and September 15 of each year.

Accounting guidance requires that cash-settled convertible debt, such as the Company's convertible senior notes, be separated into debt and equity components at issuance and each be assigned a value. The value assigned to the debt component is the estimated fair value, as of the issuance date, of a similar bond without the conversion feature. The difference between the bond cash proceeds and this estimated fair value, representing the value assigned to the equity component, is recorded as a debt discount. Debt discount is amortized using the effective interest method over the period from the origination date through the stated maturity date. The Company estimated the straight debt borrowing rates at debt origination to be 5.89% for the 2015 Notes, 3.50% for the 2018 Notes, and 3.13% for the 2020 Notes. The yield to maturity was estimated at an at-market coupon priced at par.

Debt discount after tax of $92.4 million ($154.3 million before tax) and financing costs associated with the equity component of convertible debt of $0.1 million after tax were recorded in additional paid-in capital related to the 2020 Notes at June 30, 2013. Debt discount after tax of $80.9 million ($135.2 million before tax) and financing costs associated with the equity component of convertible debt of $2.8 million after tax were recorded in additional paid-in capital related to the 2018 Notes at March 31, 2012. Debt discount after tax of $69.1 million ($115.2 million before tax) and financing costs associated with the equity component of convertible debt of $1.6 million after tax were recorded in additional paid-in-capital related to the 2015 Notes at March 31, 2010. The Company reclassified $36.7 million before tax and $54.7 million before tax out of additional paid-in capital to the mezzanine section in the Company's Unaudited Consolidated Balance Sheets at September 30, 2013 and December 31, 2012, respectively, related to the 2015 Notes.

For the three months ended September 30, 2013 and 2012, the Company recognized interest expense of $23.5 million and $16.4 million, respectively, related to convertible notes. Interest expense related to convertible notes for the three months ended September 30, 2013 and 2012 was comprised of $5.2 million and $4.3 million, respectively, for the contractual coupon interest, $17.0 million, which includes $0.6 million of original issuance discount for the 2020 Notes, and $10.9 million, respectively, related to the amortization of debt discount and $1.3 million and $1.2 million, respectively, for amortization of debt issuance costs. The effective interest rate for the three months ended September 30, 2013 and 2012 was 4.1% and 4.7%, respectively.

For the nine months ended September 30, 2013 and 2012, the Company recognized interest expense of $59.1 million and $43.2 million, respectively, related to convertible notes. Interest expense related to convertible notes for the nine months ended September 30, 2013 and 2012 was comprised of $14.1 million and $11.2 million, respectively, for the contractual coupon interest, $41.2 million, which includes $0.8 million of original issuance discount for the 2020 Notes, and $28.8 million, respectively, related to the amortization of debt discount and $3.8 million and $3.2 million, respectively, related to the amortization of debt issuance costs. The effective interest rate for the nine months ended September 30, 2013 and 2012 was 4.4% and 4.9%, respectively.