Income Taxes

Income tax expense was as follows:



	2013		2012			2011
Current income tax expense	$	49,736	$	76,928		$	60,533
Deferred income tax expense (benefit)	3,279		(6,405		)	8,167
Income tax expense, as reported	$	53,015	$	70,523		$	68,700

Reported income tax expense differed from the amounts computed by applying the U.S. federal statutory income tax rate of 35% to income before income taxes as follows:



	2013			2012			2011
Income tax expense computed at the statutory rate	$	101,808		$	107,966		$	100,182
Effect of tax-exempt interest	(46,535		)	(36,543		)	(35,741		)
Bank owned life insurance income	(1,086		)	(1,413		)	(1,416		)
Accrual adjustment for premium amortization on municipal securities	—			—			4,146
Other	(1,172		)	513			1,529
Income tax expense, as reported	$	53,015		$	70,523		$	68,700

Income tax expense for 2011 included the correction of an under-accrual of taxes that resulted from incorrectly deducting premium amortization on municipal securities for federal income tax purposes since 2008. As a result, the Corporation recognized additional income tax expense totaling $4.1 million, which included interest, related to the 2010, 2009 and 2008 tax years. Interest and/or penalties related to income taxes are reported as a component of income tax expense. Such amounts were not significant during the reported periods.

Year-end deferred taxes were as follows:



	2013			2012
Deferred tax assets:
Allowance for loan losses	$	32,353		$	36,514
Stock-based compensation	17,746			19,270
Net actuarial loss on defined benefit post-retirement benefit plans	14,070			26,423
Bonus accrual	5,301			5,006
Gain on sale of assets	2,234			2,329
Partnerships	2,208			1,808
Non-accrual loans	977			1,719
Other	4,077			4,014
Total gross deferred tax assets	78,966			97,083
Deferred tax liabilities:
Net unrealized gain on securities available for sale and effective cash flow hedging derivatives	(89,689		)	(154,603		)
Premises and equipment	(21,192		)	(22,451		)
Defined benefit post-retirement benefit plans	(14,137		)	(14,895		)
Intangible assets	(7,253		)	(6,924		)
Leases	(4,237		)	(4,717		)
Bonus accrual 481(a) adjustment	(1,091		)	(2,182		)
Prepaid expenses	(1,618		)	(1,516		)
Reserve for medical insurance	(2,171		)	(1,509		)
Other	(365		)	(355		)
Total gross deferred tax liabilities	(141,753		)	(209,152		)
Net deferred tax asset (liability)	$	(62,787	)	$	(112,069	)

No valuation allowance for deferred tax assets was recorded at December 31, 2013 and 2012 as management believes it is more likely than not that all of the deferred tax assets will be realized because they were supported by recoverable taxes paid in prior years. There were no unrecognized tax benefits during any of the reported periods.

The Corporation files income tax returns in the U.S. federal jurisdiction. The Company is no longer subject to U.S. federal income tax examinations by tax authorities for years before 2010.