22. Income taxes

The Company determines its tax provision for interim periods using an estimate of its annual effective tax rate adjusted for discrete items, if any, that are taken into account in the relevant period. Each quarter, the Company updates its estimate of the annual effective tax rate, and if its estimated tax rate changes, the Company makes a cumulative adjustment.

As of December 31, 2015, the Company had unrecognized tax benefits amounting to $26,357, including an amount of $24,935, which, if recognized, would impact the effective tax rate.

The following table summarizes activities related to the Company’s unrecognized tax benefits for uncertain tax positions from January 1, 2016 to March 31, 2016:


	2016
Opening Balance at January 1	$	26,357
Increase related to prior year tax positions, including recorded in acquisition accounting		13
Decrease related to prior year tax positions		(764	)
Decrease related to prior year tax position due to lapse of applicable statute of limitation		(166	)
Decrease related to settlements with tax authorities		(2,000	)
Effect of exchange rate changes		119

Closing Balance at March 31	$	23,559

The Company’s unrecognized tax benefits as of March 31, 2016 include an amount of $22,136, which, if recognized, would impact the effective tax rate. As of December 31, 2015 and March 31, 2016, the Company had accrued approximately $4,223 and $3,682, respectively, for interest relating to unrecognized tax benefits. During the year ended December 31, 2015 and the three months ended March 31, 2016, the company recognized approximately $1,152 and ($533), respectively, excluding exchange rate differences, in interest on unrecognized tax benefits. As of December 31, 2015 and March 31, 2016, the Company had accrued approximately $958 and $958, respectively, for penalties.