INCOME TAXES

The following table accounts for the difference between the actual tax provision and the amounts obtained by applying the statutory U.S. federal income tax rate of 35.0% to income before taxes.



	Three Months Ended March 31,
Effective Tax Rate Reconciliation (Percent)	2017		2016
Statutory federal tax rate	35.0	%	35.0	%
Salt depletion	(9.4	)	(3.4	)
Stock-based compensation	(8.4	)	—
Foreign rate differential	(3.1	)	(3.8	)
U.S. tax on foreign earnings	3.1		3.8
Dividends paid to CEOP	(0.4	)	(0.6	)
State income taxes, net	0.5		(1.4	)
Change in valuation allowance	—		0.1
Change in tax contingencies	1.1		1.6
Return to provision	5.8		—
Other, net	0.9		0.3
Effective tax rate	25.1	%	31.6	%

The effective tax rate for the three months ended March 31, 2017 included $1.5 million of tax benefit associated with stock-based compensation and $1.0 million of tax expense associated with prior year tax positions. The effective tax rate for the three months ended March 31, 2016 included $0.9 million of tax benefit associated with changes in uncertain tax positions primarily related to settlements with taxing authorities.

The condensed balance sheets include income tax receivables that are classified as other noncurrent assets of $1.5 million at March 31, 2016.

As of March 31, 2017, we had $43.3 million of gross unrecognized tax benefits, which would have a net $41.4 million impact on the effective tax rate, if recognized. As of March 31, 2016, we had $33.5 million of gross unrecognized tax benefits, of which $31.9 million would have impacted the effective tax rate, if recognized. The amount of unrecognized tax benefits was as follows:



	March 31,
	2017			2016
	($ in millions)
Balance at beginning of year	$	38.4		$	35.1
Increases for prior year tax positions	4.9			—
Decreases for prior year tax positions	(0.7		)	(1.6		)
Increases for current year tax positions	0.7			—
Balance at end of period	$	43.3		$	33.5

As of March 31, 2017, we believe it is reasonably possible that our total amount of unrecognized tax benefits will decrease by approximately $12.9 million over the next twelve months. The anticipated reduction primarily relates to settlements with taxing authorities and the expiration of federal, state and foreign statutes of limitation.

We operate globally and file income tax returns in numerous jurisdictions. Our tax returns are subject to examination by various federal, state and local tax authorities. Our U.S. federal income tax returns are under examination by the Internal Revenue Service (IRS) for tax years 2008 and 2010 to 2012. In connection with the Acquisition, TDCC retained liabilities relating to taxes to the extent arising prior to the Closing Date. We believe we have adequately provided for all tax positions; however, amounts asserted by taxing authorities could be greater than our accrued position. For our primary tax jurisdictions, the tax years that remain subject to examination are as follows:



	Tax Years
U.S. federal income tax	2008; 2010 - 2016
U.S. state income tax	2006 - 2016
Canadian federal income tax	2012 - 2016
Brazil	2014 - 2016
Germany	2015 - 2016
China	2014 - 2016
The Netherlands	2014 - 2016
South Korea	2014 - 2016