BENEFIT PLANS

NOTE 10(a) Pension and Other Postretirement Benefits Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three months ended March 31 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan.



	Defined Benefit Pension Plans						OPEB Plans
Alliant Energy	2018			2017			2018			2017
Service cost		$3.0			$3.1			$1.1			$1.2
Interest cost	11.7			12.8			1.9			2.2
Expected return on plan assets	(17.4		)	(16.4		)	(1.5		)	(1.5		)
Amortization of prior service credit	(0.2		)	(0.1		)	—			(0.1		)
Amortization of actuarial loss	8.8			9.4			0.8			1.0
		$5.9			$8.8			$2.3			$2.8



	Defined Benefit Pension Plans						OPEB Plans
IPL	2018			2017			2018			2017
Service cost		$1.8			$1.8			$0.4			$0.5
Interest cost	5.3			5.9			0.8			0.9
Expected return on plan assets	(8.1		)	(7.7		)	(1.1		)	(1.1		)
Amortization of actuarial loss	3.7			4.0			0.3			0.5
		$2.7			$4.0			$0.4			$0.8



	Defined Benefit Pension Plans						OPEB Plans
WPL	2018			2017			2018			2017
Service cost		$1.1			$1.2			$0.4			$0.5
Interest cost	5.0			5.5			0.8			0.9
Expected return on plan assets	(7.6		)	(7.1		)	(0.2		)	(0.2		)
Amortization of prior service credit	—			—			—			(0.1		)
Amortization of actuarial loss	4.3			4.6			0.5			0.4
		$2.8			$4.2			$1.5			$1.5

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three months ended March 31 was as follows (in millions):



	Alliant Energy				IPL				WPL
	2018		2017		2018		2017		2018		2017
Compensation expense		$3.3		$3.2		$1.8		$1.7		$1.3		$1.4
Income tax benefits	0.9		1.3		0.5		0.7		0.4		0.5

As of March 31, 2018, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $14.6 million, $8.1 million and $5.9 million, respectively, which is expected to be recognized over a weighted average period of between one and two years.

Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the three months ended March 31, 2018, with amounts representing the target number of awards, was as follows:



	Performance Shares		Performance Units
Nonvested awards, January 1	223,511		71,737
Granted	74,163		19,840
Vested	(90,806	)	(31,910	)
Nonvested awards, March 31	206,868		59,667

Vested Awards - During the three months ended March 31, 2018, certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:



	Performance Shares			Performance Units
Performance awards vested	90,806			31,910
Percentage of target number of performance awards	137.5		%	137.5		%
Aggregate payout value (in millions)		$5.3			$1.4
Payout - cash (in millions)		$4.9			$1.4
Payout - common stock shares issued	5,078			N/A

Fair Value of Awards - At March 29, 2018, Alliant Energy’s common stock closing price was $40.86. Additional information related to fair values of nonvested performance shares and performance units at March 31, 2018, by year of grant, was as follows:



	Performance Shares									Performance Units
	2018 Grant			2017 Grant			2016 Grant			2018 Grant			2017 Grant			2016 Grant
Nonvested awards at target	74,163			65,350			67,355			19,840			18,600			21,227
Estimated payout percentage based on performance criteria	100		%	115		%	160		%	100		%	115		%	160		%
Fair values of each nonvested award		$40.86			$46.99			$65.38			$40.86			$46.99			$65.38

Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the three months ended March 31, 2018, with amounts representing the target number of units, was as follows:

Restricted Stock Units - A summary of the restricted stock units activity for the three months ended March 31, 2018, was as follows:



Nonvested units, January 1	113,749
Granted	63,568
Nonvested units, March 31	177,317

Benefit Plans

BENEFIT PLANS

NOTE 10(a) Pension and Other Postretirement Benefits Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three months ended March 31 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan.



	Defined Benefit Pension Plans						OPEB Plans
Alliant Energy	2018			2017			2018			2017
Service cost		$3.0			$3.1			$1.1			$1.2
Interest cost	11.7			12.8			1.9			2.2
Expected return on plan assets	(17.4		)	(16.4		)	(1.5		)	(1.5		)
Amortization of prior service credit	(0.2		)	(0.1		)	—			(0.1		)
Amortization of actuarial loss	8.8			9.4			0.8			1.0
		$5.9			$8.8			$2.3			$2.8



	Defined Benefit Pension Plans						OPEB Plans
IPL	2018			2017			2018			2017
Service cost		$1.8			$1.8			$0.4			$0.5
Interest cost	5.3			5.9			0.8			0.9
Expected return on plan assets	(8.1		)	(7.7		)	(1.1		)	(1.1		)
Amortization of actuarial loss	3.7			4.0			0.3			0.5
		$2.7			$4.0			$0.4			$0.8



	Defined Benefit Pension Plans						OPEB Plans
WPL	2018			2017			2018			2017
Service cost		$1.1			$1.2			$0.4			$0.5
Interest cost	5.0			5.5			0.8			0.9
Expected return on plan assets	(7.6		)	(7.1		)	(0.2		)	(0.2		)
Amortization of prior service credit	—			—			—			(0.1		)
Amortization of actuarial loss	4.3			4.6			0.5			0.4
		$2.8			$4.2			$1.5			$1.5

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three months ended March 31 was as follows (in millions):



	Alliant Energy				IPL				WPL
	2018		2017		2018		2017		2018		2017
Compensation expense		$3.3		$3.2		$1.8		$1.7		$1.3		$1.4
Income tax benefits	0.9		1.3		0.5		0.7		0.4		0.5

As of March 31, 2018, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $14.6 million, $8.1 million and $5.9 million, respectively, which is expected to be recognized over a weighted average period of between one and two years.

Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the three months ended March 31, 2018, with amounts representing the target number of awards, was as follows:



	Performance Shares		Performance Units
Nonvested awards, January 1	223,511		71,737
Granted	74,163		19,840
Vested	(90,806	)	(31,910	)
Nonvested awards, March 31	206,868		59,667

Vested Awards - During the three months ended March 31, 2018, certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:



	Performance Shares			Performance Units
Performance awards vested	90,806			31,910
Percentage of target number of performance awards	137.5		%	137.5		%
Aggregate payout value (in millions)		$5.3			$1.4
Payout - cash (in millions)		$4.9			$1.4
Payout - common stock shares issued	5,078			N/A

Fair Value of Awards - At March 29, 2018, Alliant Energy’s common stock closing price was $40.86. Additional information related to fair values of nonvested performance shares and performance units at March 31, 2018, by year of grant, was as follows:



	Performance Shares									Performance Units
	2018 Grant			2017 Grant			2016 Grant			2018 Grant			2017 Grant			2016 Grant
Nonvested awards at target	74,163			65,350			67,355			19,840			18,600			21,227
Estimated payout percentage based on performance criteria	100		%	115		%	160		%	100		%	115		%	160		%
Fair values of each nonvested award		$40.86			$46.99			$65.38			$40.86			$46.99			$65.38

Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the three months ended March 31, 2018, with amounts representing the target number of units, was as follows:

Restricted Stock Units - A summary of the restricted stock units activity for the three months ended March 31, 2018, was as follows:



Nonvested units, January 1	113,749
Granted	63,568
Nonvested units, March 31	177,317

Benefit Plans

BENEFIT PLANS

NOTE 10(a) Pension and Other Postretirement Benefits Plans -

Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three months ended March 31 are included in the tables below (in millions). The service cost component of net periodic benefit costs is included in “Other operation and maintenance” expenses in the income statements and all other components of net periodic benefit costs are included in “Other (income) and deductions” in the income statements. In IPL’s and WPL’s tables below, the defined benefit pension plan amounts represent those respective amounts for their bargaining unit employees covered under the qualified plans that they sponsor, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Alliant Energy and Corporate Services sponsored qualified and non-qualified defined benefit pension plans. In IPL’s and WPL’s tables below, the OPEB plan amounts represent respective amounts for their employees, as well as amounts directly assigned to them related to their current and former non-bargaining employees who are participants in the Corporate Services sponsored OPEB plan.



	Defined Benefit Pension Plans						OPEB Plans
Alliant Energy	2018			2017			2018			2017
Service cost		$3.0			$3.1			$1.1			$1.2
Interest cost	11.7			12.8			1.9			2.2
Expected return on plan assets	(17.4		)	(16.4		)	(1.5		)	(1.5		)
Amortization of prior service credit	(0.2		)	(0.1		)	—			(0.1		)
Amortization of actuarial loss	8.8			9.4			0.8			1.0
		$5.9			$8.8			$2.3			$2.8



	Defined Benefit Pension Plans						OPEB Plans
IPL	2018			2017			2018			2017
Service cost		$1.8			$1.8			$0.4			$0.5
Interest cost	5.3			5.9			0.8			0.9
Expected return on plan assets	(8.1		)	(7.7		)	(1.1		)	(1.1		)
Amortization of actuarial loss	3.7			4.0			0.3			0.5
		$2.7			$4.0			$0.4			$0.8



	Defined Benefit Pension Plans						OPEB Plans
WPL	2018			2017			2018			2017
Service cost		$1.1			$1.2			$0.4			$0.5
Interest cost	5.0			5.5			0.8			0.9
Expected return on plan assets	(7.6		)	(7.1		)	(0.2		)	(0.2		)
Amortization of prior service credit	—			—			—			(0.1		)
Amortization of actuarial loss	4.3			4.6			0.5			0.4
		$2.8			$4.2			$1.5			$1.5

NOTE 10(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three months ended March 31 was as follows (in millions):



	Alliant Energy				IPL				WPL
	2018		2017		2018		2017		2018		2017
Compensation expense		$3.3		$3.2		$1.8		$1.7		$1.3		$1.4
Income tax benefits	0.9		1.3		0.5		0.7		0.4		0.5

As of March 31, 2018, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $14.6 million, $8.1 million and $5.9 million, respectively, which is expected to be recognized over a weighted average period of between one and two years.

Performance Shares and Performance Units - A summary of the performance shares and performance units activity for the three months ended March 31, 2018, with amounts representing the target number of awards, was as follows:



	Performance Shares		Performance Units
Nonvested awards, January 1	223,511		71,737
Granted	74,163		19,840
Vested	(90,806	)	(31,910	)
Nonvested awards, March 31	206,868		59,667

Vested Awards - During the three months ended March 31, 2018, certain performance shares and performance units that were granted in 2015 vested, resulting in payouts (a combination of cash and common stock for the performance shares and cash only for the performance units) as follows:



	Performance Shares			Performance Units
Performance awards vested	90,806			31,910
Percentage of target number of performance awards	137.5		%	137.5		%
Aggregate payout value (in millions)		$5.3			$1.4
Payout - cash (in millions)		$4.9			$1.4
Payout - common stock shares issued	5,078			N/A

Fair Value of Awards - At March 29, 2018, Alliant Energy’s common stock closing price was $40.86. Additional information related to fair values of nonvested performance shares and performance units at March 31, 2018, by year of grant, was as follows:



	Performance Shares									Performance Units
	2018 Grant			2017 Grant			2016 Grant			2018 Grant			2017 Grant			2016 Grant
Nonvested awards at target	74,163			65,350			67,355			19,840			18,600			21,227
Estimated payout percentage based on performance criteria	100		%	115		%	160		%	100		%	115		%	160		%
Fair values of each nonvested award		$40.86			$46.99			$65.38			$40.86			$46.99			$65.38

Performance Restricted Stock Units - A summary of the performance restricted stock units activity for the three months ended March 31, 2018, with amounts representing the target number of units, was as follows:

Restricted Stock Units - A summary of the restricted stock units activity for the three months ended March 31, 2018, was as follows:



Nonvested units, January 1	113,749
Granted	63,568
Nonvested units, March 31	177,317

Weighted Average
Grant Date Fair Value

Nonvested units, January 1

Nonvested units, March 31