Income Taxes

A reconciliation of the U.S. federal statutory tax rate to the Company’s effective income tax rate is as follows:



	Three months ended March 31,
	2017		2016
U.S. federal statutory tax rate	(35.0	)%	(35.0	)%
State income taxes, net of federal benefit	(2.2	)	(3.0	)
Non-U.S. income taxed at different rates	0.5		0.5
Excess tax benefit related to stock-based awards	6.2		—
Other	0.4		0.5
Effective income tax rate	(30.1	)%	(37.0	)%

Fluctuations in effective tax rates have historically been impacted by permanent tax differences with no associated income tax impact, changes in state apportionment factors, including the effect on state deferred tax assets and liabilities, and benefits of non-U.S. income taxed at lower rates. Changes in the effective tax rate during the three months ended March 31, 2017, included the Company implementing ASU No. 2016-09 which requires accounting for excess tax benefits and tax deficiencies as discrete items in the period in which they occur.

In January 2017, the Internal Revenue Service notified the Company that it will examine the Company’s federal tax returns for the year ended December 31, 2014. No adjustments have been asserted, and management believes that sustained adjustments, if any, would not have a material effect on the Company’s financial position, results of operations, or liquidity.