for streaming delivery, payment processing fees and customer service call centers due to our growing member base.

Cash used in investing activities increased $11.2 million, primarily due to an increase of $17.7 million in the acquisition of DVD content library and a $13.9 million increase in the purchase of property and equipment primarily due to investments in our streaming delivery network. Cash outflow was offset by a $23.2 million increase in the proceeds from sales and maturities of short-term investments, net of purchases.

Cash provided by financing activities increased $470.7 million. In the first quarter of 2013, we issued $500.0 million of 5.375% Notes, with net proceeds of $490.6 million after payment of debt issuance costs. This was offset by the $219.4 million redemption of our 8.50% Senior Notes. Financing activities were further impacted by $197.6 million of increased cash flows provided by stock option exercises.

Free cash flow was $75.3 million lower than net income for the year ended December 31, 2012 primarily due to $143.9 million of content cash payments over expense and $5.3 million non-favorable other working capital differences partially offset by $73.9 million non-cash stock-based compensation expense.



Contractual Obligations

For the purpose of this table, contractual obligations for purchases of goods or services are defined as agreements that are enforceable and legally binding and that specify all significant terms, including: fixed or minimum quantities to be purchased; fixed, minimum or variable price provisions; and the approximate timing of the transaction. The expected timing of payment of the obligations discussed below is estimated based on information available to us as of December 31, 2014. Timing of payments and actual amounts paid may be different depending on the time of receipt of goods or services or changes to agreed-upon amounts for some obligations. The following table summarizes our contractual obligations at December 31, 2014:

 

 

 

Payments due by Period

Contractual obligations (in thousands):

(1)

As of December 31, 2014, streaming content obligations were comprised of $2.1 billion included in "Current content liabilities" and $1.6 billion of "Non-current content liabilities" on the Consolidated Balance Sheets and $5.8 billion of obligations that are not reflected on the Consolidated Balance Sheets as they do not yet meet the criteria for asset recognition.

Streaming content obligations increased $2.2 billion from $7.3 billion as of December 31, 2013 to $9.5 billion as of December 31, 2014 primarily due to multi-year commitments associated with our latest market launches in Europe and the continued expansion of our exclusive and original programming.

A streaming content obligation is incurred at the time we enter into an agreement to obtain future titles. Once a title becomes available, a content liability is generally recorded on the Consolidated Balance Sheets. Certain agreements include the obligation to license rights for unknown future titles, the ultimate quantity and / or fees for which are not yet determinable as of the reporting date. Because the amount is not reasonably