11.

Income Taxes

We operate on a global basis and are subject to numerous and complex tax laws and regulations. Our income tax filings are regularly under audit in multiple federal, state and foreign jurisdictions. Income tax audits may require an extended period of time to reach resolution and may result in significant income tax adjustments when interpretation of tax laws or allocation of company profits is disputed. We estimate that the amount of unrecognized tax benefits may change within the next twelve months between $0 and $60 million due to changes in audit status, expiration of statutes of limitations, settlements of tax assessments and other events which could impact our determination of unrecognized tax benefits.

During the second quarter of 2011, the Internal Revenue Service (IRS) concluded its examination of our U.S. federal returns for years 2005 through 2007 and during the fourth quarter of 2013, the IRS concluded its examination of our U.S. federal returns for years 2008 through 2009. For years 2006 through 2009, the IRS has proposed adjustments reallocating profits between certain of our U.S. and foreign subsidiaries. We have disputed these proposed adjustments and continue to pursue resolution with the IRS. Although the ultimate timing for resolution of the disputed tax issues is uncertain, we may resolve certain tax matters with the IRS within the next twelve months, and pay amounts for other unresolved tax matters in order to limit the potential impact of IRS interest charges. Final resolution of these matters could have a material impact on our income tax expense, results of operations and cash flows for future periods.

In the three month period ended March 31, 2014, our effective tax rate was 22.7 percent. Our effective tax rate was lower than the U.S. statutory income tax rate of 35 percent primarily due to income earned in foreign locations with lower tax rates as well as an international reorganization resulting in the release of a valuation allowance on foreign net operating loss carryforwards.