Provisions for income taxes have been calculated in accordance with the provisions of ASC 740. Income from continuing operations before income taxes and a summary of the components of income tax expense in the Consolidated Statements of Income are shown below:

YEARS ENDED DECEMBER 31	2020			2019		2018
(in millions)
Income from continuing operations before income taxes	$	444.8		$	522.1	$	282.5
Income tax expense (benefit):
Current	$	105.9		$	80.5	$	46.2
Deferred		(23.1	)		12.6		(2.7	)
Total income tax expense	$	82.8		$	93.1	$	43.5

As noted above, in Note 2 – “Discontinued Operations,” on June 14, 2019, the U.S. Department of the Treasury issued regulations that changed the taxation of certain non-U.S. income. These regulations were applied retroactively to January 1, 2018. As a result, the Company incurred additional federal income tax of $1.2 million from the 2018 sale of Chaucer. In accordance with ASC 740, the Company has recorded a provision for this amount as a component of income tax expense in continuing operations in its Consolidated Statements of Income for the year ended December 31, 2019.

The income tax expense attributable to the consolidated results of continuing operations is different from the amount determined by multiplying income from continuing operations before income taxes by the U.S. statutory federal income tax rate of 21% . The sources of the difference and the tax effects of each were as follows:

YEARS ENDED DECEMBER 31	2020			2019			2018
(in millions)
Expected income tax expense	$	93.4		$	109.6		$	59.3
Tax difference related to investment disposals and maturities		(9.2	)		(14.8	)		(9.2	)
Stock-based compensation windfall benefit		(2.1	)		(3.0	)		(2.3	)
Dividend received deduction		(1.1	)		(1.3	)		(1.2	)
Tax-exempt interest		(0.2	)		(0.3	)		(0.4	)
Nondeductible expenses		1.8			1.7			1.6
Effect of changes in the tax law and rates		—			1.2			(4.3	)
Other, net		0.2			—			—
Income tax expense	$	82.8		$	93.1		$	43.5
Effective tax rate		18.6	%		17.8	%		15.4	%

The following are the components of the Company’s deferred tax assets and liabilities, (excluding those associated with its discontinued operations).

DECEMBER 31	2020			2019
(in millions)
Deferred tax assets:
Loss, LAE and unearned premium reserves, net	$	150.8		$	139.9
Employee benefit plans		6.0			7.6
Other		16.9			8.3
Total deferred tax assets		173.7			155.8
Deferred tax liabilities:
Investments, net		146.7			87.9
Deferred acquisition costs		100.3			98.1
Software capitalization		24.0			21.0
Other		—			0.6
Total deferred tax liabilities		271.0			207.6
Net deferred tax liability	$	(97.3	)	$	(51.8	)

Deferred tax assets are reduced by a valuation allowance if it is more likely than not that all or some portion of the deferred tax assets will not be realized. The Company believes it is more likely than not that the deferred tax assets will be realized; therefore there was no valuation allowance required at December 31, 2020 or 2019.

In prior years, the Company completed several transactions which resulted in, for tax purposes only, realized gains in its investment portfolio. As a result of these transactions, the Company was able to utilize capital losses carried forward and to release the valuation allowance recorded against the deferred tax asset related to these losses. The releases of valuation allowances were recorded as a benefit in accumulated other comprehensive income. Previously unrealized benefits of $9.2 million, $14.8 million and $9.2 million, were recognized as part of income from continuing operations during 2020, 2019 and 2018, respectively. The remaining amount of $11.6 million in accumulated other comprehensive income will be released into income from continuing operations in future years, as the investment securities subject to these transactions are sold or mature.

The table below provides a reconciliation of the beginning and ending liability for uncertain tax positions as follows:

YEARS ENDED DECEMBER 31	2020			2019			2018
(in millions)
Liability at beginning of year, net	$	1.3		$	3.0		$	3.0
Additions for tax positions of current year		—			—			—
Subtractions as a result of a lapse of the applicable statute of limitations		(0.4	)		(1.7	)		—
Liability at end of year, net	$	0.9		$	1.3		$	3.0

There were no tax positions at December 31, 2020, 2019 and 2018 for which the ultimate deductibility was highly certain, but for which there was uncertainty about the timing of such deductibility. Because of the impact of deferred tax accounting, other than interest and penalties, a change in the timing of deductions would not impact the annual effective tax rate.

The Company recognizes interest and penalties related to unrecognized tax benefits in federal income tax expense. For the years ended December 31, 2020, 2019 and 2018 the Company recognized a de minimis amount of net interest and has not recognized any penalties associated with unrecognized tax benefits. During 2020 and 2019, the Company released accrued interest of $0.1 million and $0.3 million, respectively, due to the expirations of a statute of limitations.

In 2021, the Company is expecting to release the remaining $0.9 million of liability due to the expiration of a statute of limitations.

The Company and its subsidiaries file income tax returns in the U.S. federal jurisdiction and various state jurisdictions, as well as foreign jurisdictions. The Company and its subsidiaries are subject to U.S. federal and state income tax examinations and foreign examinations for years after 2016.