Income Taxes

The following table provides a comparative summary of our income tax provision and effective tax rate for the three and nine months ended September 30, 2016 and 2015:



	Three months ended						Nine months ended
	September 30,						September 30,
	2016			2015			2016			2015
Provision for income taxes	$	63,776		$	323,116		$	165,113		$	345,815
Effective tax rate	40.3		%	231.9		%	35.0		%	81.6		%

The tax provision for the three and nine months ended September 30, 2016 and 2015 is attributable to the U.S. federal, state and foreign income taxes on our profitable operations. The decrease in the effective tax rate for the three and nine months ended September 30, 2016 as compared to the same period in the prior year is primarily attributable to a one-time tax charge recorded in Q3 2015 of $315,569 associated with integration of the Synageva business, partially offset by the deferred tax cost associated with a distribution of 2016 earnings from our captive foreign partnership. The partnership earnings we distributed were not previously subject to our indefinite reinvestment assertion.

Tax years 2013 and 2014 are currently under review by the Examination Division of the Internal Revenue Service (IRS). As of September 30, 2016, we have not been notified of any significant proposed adjustments by the IRS.

We continue to maintain a valuation allowance against certain deferred tax assets where realization is not certain.