Edgar Filing: ALLIANT ENERGY CORP

Document

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 11-K



x	ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2017



¨	TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from _____________ to _____________

Commission File Number: 1-9894


A.	Full title of the plan and address of the plan, if different from that of the issuer named below:

ALLIANT ENERGY CORPORATION 401(k) SAVINGS PLAN


B.	Name of issuer of the securities held pursuant to the plan and the address of its principal executive office:

ALLIANT ENERGY CORPORATION

4902 North Biltmore Lane

Madison, Wisconsin 53718

REQUIRED INFORMATION

The following financial statements and schedules of the Alliant Energy Corporation 401(k) Savings Plan, prepared in accordance with the financial reporting requirements of the Employee Retirement Income Security Act of 1974, as amended, are filed herewith.

Page 1 of 15 pages

Exhibit Index is on page 14

ALLIANT ENERGY CORPORATION

401(k) SAVINGS PLAN

FINANCIAL STATEMENTS AS OF DECEMBER 31, 2017 AND 2016

AND FOR THE YEAR ENDED DECEMBER 31, 2017,

SUPPLEMENTAL SCHEDULE AS OF DECEMBER 31, 2017, AND

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

TABLE OF CONTENTS



	Page Number
REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM	3
FINANCIAL STATEMENTS
Statements of Net Assets Available for Benefits as of December 31, 2017 and 2016	4
Statement of Changes in Net Assets Available for Benefits for the Year Ended December 31, 2017	5
NOTES TO FINANCIAL STATEMENTS
1. Description of the Plan	6
2. Summary of Significant Accounting Policies	7
3. Tax Status	8
4. Plan Termination Provisions	8
5. Withdrawals and Distributions	9
6. Fair Value Measurements	9
7. Related Party Transactions	10
8. Reconciliation to Form 5500	11
SUPPLEMENTAL SCHEDULE
Form 5500, Schedule H, Part IV, line 4i - Schedule of Assets (Held at End of Year) as of December 31, 2017	12
SIGNATURES	13
EXHIBIT INDEX	14
CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM	15

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the Plan Participants and Plan Administrator of Alliant Energy Corporation 401(k) Savings Plan:

Opinion on the Financial Statements

We have audited the accompanying statements of net assets available for benefits of Alliant Energy Corporation 401(k) Savings Plan (the “Plan”) as of December 31, 2017 and 2016, the related statement of changes in net assets available for benefits for the year ended December 31, 2017, and the related notes (collectively referred to as the “financial statements”). In our opinion, the financial statements present fairly, in all material respects, the net assets available for benefits of the Plan as of December 31, 2017 and 2016, and the changes in net assets available for benefits for the year ended December 31, 2017, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

These financial statements are the responsibility of the Plan’s management. Our responsibility is to express an opinion on the Plan’s financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Plan in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Report on Supplemental Schedule

The supplemental schedule of assets (held at end of year) as of December 31, 2017, has been subjected to audit procedures performed in conjunction with the audit of the Plan’s financial statements. The supplemental schedule is the responsibility of the Plan’s management. Our audit procedures included determining whether the supplemental schedule reconciles to the financial statements or the underlying accounting and other records, as applicable, and performing procedures to test the completeness and accuracy of the information presented in the supplemental schedule. In forming our opinion on the supplemental schedule, we evaluated whether the supplemental schedule, including its form and content, is presented in compliance with the Department of Labor’s Rules and Regulations for Reporting and Disclosure under the Employee Retirement Income Security Act of 1974. In our opinion, such schedule is fairly stated, in all material respects, in relation to the financial statements as a whole.

/s/ DELOITTE & TOUCHE LLP

DELOITTE & TOUCHE LLP

Milwaukee, Wisconsin

June 27, 2018

We have served as the auditor of the Plan since 2002.

ALLIANT ENERGY CORPORATION

401(k) SAVINGS PLAN

STATEMENTS OF NET ASSETS AVAILABLE FOR BENEFITS



	December 31, 2017		December 31, 2016
Investments at fair value (Refer to Note 6)		$1,034,631,020		$877,374,804
Fully benefit-responsive investment contracts at contract value (Refer to Note 2)	79,660,217		79,926,540
Notes receivable from participants	9,868,475		10,068,495
Employer contribution receivable	556,555		475,126
Net assets available for benefits		$1,124,716,267		$967,844,965

The accompanying Notes to Financial Statements are an integral part of these statements.

ALLIANT ENERGY CORPORATION

401(k) SAVINGS PLAN

STATEMENT OF CHANGES IN NET ASSETS AVAILABLE FOR BENEFITS



	For the Year Ended December 31,
	2017
Net assets available for benefits - beginning of year		$967,844,965
Contributions:
Cash contributions from employees	38,722,019
Cash contributions from employer	25,021,029
Rollovers from other qualified plans	4,104,955
Investment income:
Interest and dividends	29,032,915
Net appreciation in fair value of investments	144,302,465
Net investment income	173,335,380

Interest income on notes receivable from participants	417,036
Distributions to participants	(84,729,117		)
Net increase	156,871,302
Net assets available for benefits - end of year		$1,124,716,267

The accompanying Notes to Financial Statements are an integral part of this statement.

ALLIANT ENERGY CORPORATION

401(k) SAVINGS PLAN

NOTES TO FINANCIAL STATEMENTS

AS OF DECEMBER 31, 2017 AND 2016 AND

FOR THE YEAR ENDED DECEMBER 31, 2017

NOTE 1. DESCRIPTION OF THE PLAN

The Alliant Energy Corporation 401(k) Savings Plan (the Plan) is a qualified defined contribution plan under Section 401(k) of the Internal Revenue Code (the Code), as amended, and meets the applicable requirements of the Employee Retirement Income Security Act of 1974, as amended. The following brief description of the Plan is provided for general information purposes only. More complete information regarding the Plan is provided in the plan document and summary plan description, which have been made available to all eligible Plan participants (participants). The Plan is administered by the Alliant Energy Corporation Total Compensation Committee (the Committee) and the Plan sponsor is Alliant Energy Corporate Services, Inc. (a direct subsidiary of Alliant Energy Corporation). The Committee reserves the right to terminate, amend or modify the Plan if future conditions warrant such action.

Any regular employee of Alliant Energy Corporation and its participating subsidiaries (the Company) age 18 and over may participate in the Plan. Regular full-time employees and regular part-time employees customarily scheduled to work at least half-time may participate immediately following 30 days of service. Part-time employees customarily scheduled to work less than half-time may participate after 12 months of service during which he or she has earned at least 1,000 paid hours. An initial automatic 6% pre-tax employee contribution rate has been applied to newly hired employees, unless the employee made a contrary election within 30 days of their hire date.

An Employee Stock Ownership Plan is in place within the Plan. Under these provisions, participants have the option to elect to receive cash for any dividends paid on Company common stock within the Plan or to have the dividends reinvested in additional shares based on the current market price.

On April 20, 2016, the Company’s Board of Directors approved a two-for-one common stock split. Plan participants holding shares of Company common stock within the Plan at the close of business on May 4, 2016 received one additional share of Company common stock for each share held on that date. Participant’s account balances did not change as a result of the stock split. The additional shares were distributed on May 19, 2016 and post-split trading began on May 20, 2016.

In January 2018, the Company’s Board of Directors authorized the redemption of Company common stock purchase rights under its amended and restated Shareowner Rights Agreement, which were redeemed to Plan participants holding shares of Company common stock within the Plan at the close of business on January 31, 2018. The redemption payment was made to applicable participant accounts on February 21, 2018.

The Company provides matching contributions of $0.50 for each $1 contributed by the participant up to the first 8% of each respective participant’s eligible compensation. In addition, the Company provides a contribution into each active employee’s 401(k) account each pay period based on a percentage of their eligible compensation (non-elective Company cash contribution) as follows:



Age Plus Years of Service		Company Contribution
Less than or equal to 49		4%
50 - 69		5%
70+		6%

Company matching contributions and the non-elective Company cash contributions are invested at each participant’s discretion. Participants may subsequently re-designate the distribution of future contributions or transfer existing balances between investment funds on a daily basis, subject to the limits set forth in the Plan. The Plan allows participants to transfer vested balances to an in-plan Roth conversion account within the Plan, subject to the limits and terms set forth in the Plan.

An “additional” Company contribution is contributed to the accounts of active participants, as of the last day of the Plan year, who contributed at least the maximum level of their compensation eligible to be matched by the Company and did not receive the maximum level of Company matching contributions based on their contributions during the Plan year.

There are certain exceptions to the Company matching contributions and non-elective Company cash contributions described above for bargaining unit employees. These exceptions are dependent on the bargaining unit in which the employee participates and the employee’s date of hire. These exceptions include certain employees being ineligible for the non-elective Company cash contribution and the Company matching contribution being limited to $0.50 for each $1 contributed by the participant up to the first 6% of each respective participant’s eligible compensation.

Employee contribution limits for 2017 were as follows:



Eligible employee annual contribution limit as a percentage of compensation	50%
Maximum annual contribution limit (a)	$18,000


(a)	Participants who were at least age 50 by December 31, 2017 were eligible to make additional catch-up contributions of up to $6,000 in 2017. These additional catch-up contributions were not eligible for any Company match.

Participants are immediately vested in their respective employee and employer contributions, except for the non-elective Company cash contribution which is subject to a three-year cliff vesting schedule for all new hires. At December 31, 2017 and 2016, forfeited nonvested accounts totaled $147,148 and $160,449, respectively. These accounts will be used to reduce future employer contributions. In 2017, employer contributions were reduced by $369,116 from forfeited nonvested accounts.

Contributions under the Plan are held and invested, until distribution, in a Trust Fund maintained by Great-West Trust Company, LLC (the Trustee). Individual accounts are maintained by Great-West Financial Retirement Plan Services, LLC (the Recordkeeper, or Empower Retirement) for each participant. In 2016, the Self-Managed Brokerage Accounts service provider changed from J.P. Morgan Securities, LLC to Charles Schwab & Co. Each participant’s account is credited with the participant’s contributions, Company contributions and an allocation of Plan earnings, and charged with withdrawals and an allocation of Plan losses and administrative expenses. Allocations are based on participant earnings or account balances, as defined. Participant rollovers are allowed into the Plan from other qualified plans. The benefit to which a participant is entitled is the benefit that can be provided from the participant’s vested account balance.

The Plan has provisions under which participants who are active employees may take loans up to the lesser of $50,000 or 50% of their total account balance (a $1,000 minimum loan amount and a maximum of three loans for each participant also apply). The Committee determines the loan interest rate pursuant to the Plan. Interest rates on participant loans outstanding ranged from 4.25% to 9.25% at both December 31, 2017 and 2016. Principal and interest are repaid bi-weekly through employee payroll deductions.

NOTE 2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

NOTE 2(a) Basis of Accounting - The financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (GAAP).

NOTE 2(b) Accounting for Fully Benefit-Responsive Contracts - In accordance with Financial Accounting Standards Board (FASB) authoritative guidance, which defines reporting of fully benefit-responsive contracts held by defined-contribution pension plans, the statements of net assets available for benefits present investments at fair value except for fully benefit-responsive contracts, which are reported at contract value. Contract value is the relevant measure for the fully benefit-responsive investment contracts because contract value is the amount participants normally would receive if they were to initiate permitted transactions under the terms of the Plan. Certain events, such as a Plan termination or merger, initiated by the Plan sponsor, may limit the ability of the Plan to transact at contract value or may allow for the termination of the wrapper contract at less than contract value. The Committee believes the likelihood of events occurring that may limit the ability of the Plan to transact at contract value is not probable.

All guaranteed investment contracts held by the Plan are fully benefit-responsive contracts and at December 31, 2017 and 2016 all were synthetic. The contract value of all synthetic guaranteed investment contract investments was $79,660,217 and $79,926,540 at December 31, 2017 and 2016, respectively. The synthetic guaranteed investment contracts are comprised of investments in common collective trusts owned by the Plan and an investment contract issued by an insurance company or other financial institution, designed to provide a contract value “wrapper” around the fixed income portfolio to guarantee a specific interest rate. The guaranteed investment contract wrappers provide protection when the market value of the underlying assets is less than the contract value.

NOTE 2(c) Valuation of Investments and Income Recognition - The Plan’s investments are stated at fair value except for fully benefit-responsive investment contracts, which are reported at contract value. Plan investments are carried at fair value as determined by quoted market prices or the net asset value (NAV) of shares held by the Plan on the valuation date. Interest

income is accrued when earned. Dividend income is recorded on the ex-dividend date. Investment transactions are recorded on the trade date.

NOTE 2(d) Net Appreciation in Fair Value of Investments - Net realized and unrealized appreciation is recorded in the accompanying statement of changes in net assets available for benefits as “Net appreciation in fair value of investments.”

NOTE 2(e) Notes Receivable from Participants - Participant loans are carried at their unpaid principal balance, plus any accrued but unpaid interest.

NOTE 2(f) Distribution of Benefits - Benefit distributions to participants are recorded when paid.

NOTE 2(g) Expenses - All expenses paid through the Plan are recorded with investment earnings (losses) in the accompanying statement of changes in net assets available for benefits. Recordkeeping fees are reported separately from investment earnings on individual participant statements and are paid by the Plan participants. Investment management fees are paid from investment earnings prior to crediting earnings to the individual participant account balances, but can be identified in the investment fund information supplied to participants from Empower Retirement. Certain other Plan administrative expenses are absorbed by the Company. Expenses incurred in maintaining Self-Managed Brokerage Accounts are the responsibility of the respective Plan participants.

NOTE 2(h) Use of Estimates - The preparation of financial statements in conformity with GAAP requires the Plan administrator to make estimates and assumptions that affect the reported amounts of net assets available for benefits at the date of the financial statements and the reported amounts of changes in net assets available for benefits during the reporting period. Actual results could differ from those estimates.

NOTE 2(i) Risk and Uncertainties - The Plan invests in various investments, including registered investment companies, common/collective trusts, common stock of the Company and synthetic investment contracts. The Plan also offers a Self-Managed Brokerage Account option, which allows participants to invest in a wide range of mutual funds and exchange traded funds. Investments, in general, are exposed to various risks, such as interest rate, credit and overall market volatility risks. Due to the level of risk associated with certain investments, it is reasonably possible that changes in the values of certain investments may occur in the near term and that such changes could materially affect the amounts reported in the financial statements. As of December 31, 2017, there was a significant concentration of investments in the State Street Global Advisors S&P 500 Index Fund, American Funds EuroPacific Growth Fund, Alliant Energy Corporation common stock and Winslow Large Cap Growth Fund.

NOTE 3. TAX STATUS

The Internal Revenue Service (IRS) has determined and informed the Company by a letter dated May 22, 2017, that the Plan and related trust are designed in accordance with the applicable sections of the Code. The Plan has been amended since applying for the recently received determination letter. The Committee and the Plan’s tax counsel believe that the Plan is designed and is currently being operated in compliance with the applicable requirements of the Code. Therefore, no provision for income taxes has been included in the Plan’s financial statements.

The Plan is subject to routine audits by the IRS; however, there are currently no audits for any tax periods in progress. The Committee believes the Plan is no longer subject to income tax examinations for years prior to 2014.

NOTE 4. PLAN TERMINATION PROVISIONS

Upon termination of the Plan in its entirety, each participant is entitled to receive, in accordance with the terms of the Plan, the entire balance in their account. The Company has no intention to terminate the Plan.

NOTE 5. WITHDRAWALS AND DISTRIBUTIONS

Withdrawals from participants’ account balances are allowed when participants who are actively employed reach age 59-1/2. Withdrawals are also allowed due to special “hardship” circumstances. Distributions from the Plan will be made upon termination of employment (by retirement, death, disability or otherwise) if the participant’s account balance is less than $5,000. Beneficiaries of deceased employees can remain in the Plan. If a withdrawing participant’s account balance is less than $5,000, and the participant does not make an election to either have the account paid as a direct rollover or as a cash payment, the distribution will be paid as a direct rollover to an individual retirement account established for the participant. If a withdrawing participant’s account balance exceeds $5,000, the participant may elect to defer payment until he or she is age 70-1/2. Distributions can be either in the form of a lump sum, partial distribution or substantially equal monthly, quarterly, semiannual or annual installments. The unpaid portion of all loans made to the participant, including accrued interest, will be deducted from the amount of the participant account to be distributed. Distributions payable to participants at December 31, 2017 and 2016 were $0.

NOTE 6. FAIR VALUE MEASUREMENTS

Valuation Hierarchy and Techniques - Fair value measurement accounting establishes three levels of fair value hierarchy that prioritize the inputs to valuation techniques used to measure fair value. The three levels of the fair value hierarchy and a description of the Plan’s assets and valuation techniques for each are as follows:

Level 1 - Pricing inputs are quoted prices available in active markets for identical assets or liabilities as of the reporting date. Level 1 Plan assets include investments in registered investment companies and common stocks and are valued at the closing price reported in the active market in which the individual securities are traded. Assets of participant-directed brokerage accounts at December 31, 2017 and 2016 were limited to investments in registered investment companies.

Level 2 - Pricing inputs are quoted prices for similar assets or liabilities in active markets or quoted prices for identical or similar assets or liabilities in markets that are not active as of the reporting date. The Plan did not hold any Level 2 Plan assets at December 31, 2017 and 2016.

Level 3 - Pricing inputs are unobservable inputs for assets or liabilities for which little or no market data exist and require significant management judgment or estimation. The Plan did not hold any Level 3 Plan assets at December 31, 2017 and 2016.

The fair value hierarchy gives the highest priority to quoted prices in active markets (Level 1) and the lowest priority to unobservable data (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. The lowest level input that is significant to a fair value measurement in its entirety determines the applicable level in the fair value hierarchy. Assessing the significance of a particular input to the fair value measurement in its entirety requires judgment, considering factors specific to the asset or liability.

The methods described above may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Plan believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date.

Fair Value Measurements - Items subject to fair value measurements disclosure requirements at December 31, 2017 and 2016 were as follows:



	Fair Value Measurements		Level 1		Level 2		Level 3
Assets at December 31, 2017:
Registered investment companies:
International - developed markets		$158,968,178		$158,968,178		$—		$—
U.S. large cap value	112,228,976		112,228,976		—		—
Fixed income funds	68,627,515		68,627,515		—		—
U.S. small cap growth	41,726,128		41,726,128		—		—
U.S. mid cap value	34,037,595		34,037,595		—		—
U.S. mid cap growth	24,480,646		24,480,646		—		—
International - emerging markets	21,711,594		21,711,594		—		—
U.S. small cap value	19,330,878		19,330,878		—		—
Common stocks	127,958,394		127,958,394		—		—
Participant-directed brokerage accounts	7,410,602		7,410,602		—		—
Total assets in the fair value hierarchy	616,480,506			$616,480,506		$—		$—
Assets measured at NAV (a)	418,150,514
Total assets at fair value		$1,034,631,020



	Fair Value Measurements		Level 1		Level 2		Level 3
Assets at December 31, 2016:
Registered investment companies:
International - developed markets		$119,708,215		$119,708,215		$—		$—
U.S. large cap value	97,707,876		97,707,876		—		—
Fixed income funds	62,335,763		62,335,763		—		—
U.S. small cap growth	33,724,585		33,724,585		—		—
U.S. mid cap value	26,067,745		26,067,745		—		—
U.S. mid cap growth	19,313,777		19,313,777		—		—
U.S. small cap value	17,649,427		17,649,427		—		—
International - emerging markets	15,428,440		15,428,440		—		—
Common stocks	120,513,373		120,513,373		—		—
Participant-directed brokerage accounts	5,794,002		5,794,002		—		—
Total assets in the fair value hierarchy	518,243,203			$518,243,203		$—		$—
Assets measured at NAV (a)	359,131,601
Total assets at fair value		$877,374,804

(a)

In accordance with FASB authoritative guidance, certain investments that are measured at fair value using the NAV practical expedient have not been classified in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the statement of net assets available for benefits. These Plan assets include investments in common/collective trusts, which are valued at the NAV of shares held by the Plan which is based on the fair market value of the underlying investments in the common/collective trusts. The common/collective trusts underlying assets primarily consist of traded securities that have a variety of investment strategies including domestic and international equity and fixed income funds. There are no participant redemption restrictions for these investments and no redemption notice period applicable to the Plan.

NOTE 7. RELATED PARTY TRANSACTIONS

Certain Plan investments are shares of common stock of the Company. As of December 31, 2017 and 2016, the Plan held 3,003,013 and 3,180,612 shares of Alliant Energy Corporation common stock with a cost basis of $65,602,565 and $65,544,506, and fair value of $127,958,394 and $120,513,373, respectively. In 2017 and 2016, the Plan recorded dividend income of $3,865,090 and $3,795,242, respectively, from investments in common stock of the Company. These transactions qualify as exempt party-in-interest transactions.

NOTE 8. RECONCILIATION TO FORM 5500

Net assets available for benefits in the accompanying financial statements report fully benefit-responsive investment contracts at contract value; however, the contracts are recorded at fair value in the Plan’s Form 5500. If applicable, distributions payable to participants are not included as a liability within net assets available for benefits in the accompanying financial statements, however, they are recorded as liabilities in the Plan’s Form 5500. The following table reconciles net assets available for benefits per the financial statements to the Plan’s Form 5500 as filed by the Plan:



	2017			2016
Net assets available for benefits per financial statements		$1,124,716,267			$967,844,965
Adjustments:
Contract value to fair value for fully benefit-responsive investment contracts	(830,971		)	(562,154		)
Deemed distributions of participant loans	(377,638		)	(350,225		)
Amounts reported per Form 5500		$1,123,507,658			$966,932,586

The following table reconciles the net increase in net assets available for benefits per the financial statements to the Form 5500 as filed by the Plan for 2017:



	Net Increase
Amounts reported per financial statements	$156,871,302
Adjustments:
Changes in adjustment from contract value to fair value for fully benefit-responsive investment contracts	(268,817	)
Changes in deemed distributions of participant loans	(27,413	)
Amounts reported per Form 5500	$156,575,072

ALLIANT ENERGY CORPORATION

401(k) SAVINGS PLAN

FORM 5500, SCHEDULE H, PART IV, LINE 4i - SCHEDULE OF ASSETS (HELD AT END OF YEAR)

AS OF DECEMBER 31, 2017



Identity of issue, borrower,	Description of investment including maturity date,
lessor, or similar party	rate of interest, collateral, par or maturity value	Cost (a)	Current Value
Registered Investment Companies	American Funds EuroPacific Growth Fund, 2,831,638 class R6 shares			$158,968,178
	Dodge & Cox Stock Fund, 551,196 shares		112,228,976
	PIMCO Total Return Fund, 6,370,615 class I shares		65,426,219
	Carillon Eagle Small Cap Growth Fund, 658,348 class R6 shares		41,726,128
	Vanguard Selected Value Fund, 1,088,506 shares		34,037,595
	Vanguard Mid Cap Growth Fund, 926,946 shares		24,480,646
	Aberdeen Emerging Markets Fund, 1,345,204 Institutional shares		21,711,594
	Victory Integrity Small Cap Value, 470,911 class R6 shares		19,330,878
	Vanguard Short-Term Inflation-Protected Securities Index Fund, 130,825 Admiral shares		3,201,296
Common/Collective Trusts	State Street Global Advisors S&P 500 Index Fund, 3,567,096 class N shares		212,292,126
	Winslow Large Cap Growth Fund, 2,388,084 class I shares		113,983,245
	State Street Global Advisors U.S. Bond Market Index Fund, 6,422,631 class C shares		90,199,430
	JPMorgan Intermediate Bond Fund, 5,001,856 shares		78,829,246
	JPMorgan Liquidity Fund, 1,675,713 shares		1,675,713
Corporate Stocks: Common	Alliant Energy Corporation common stock (b), 3,003,013 shares		127,958,394
Participant-Directed Brokerage Accounts	Self-Managed Brokerage Accounts		7,410,602
Participant Promissory Notes (b)	Maximum allowable loans per participant - $50,000
	Various interest rates - 4.25% to 9.25%
	Primarily maturing within 5 years		9,868,475
				$1,123,328,741


(a)	Cost value is not required to be disclosed for participant-directed investments.


(b)	Represents party known to be a party-in-interest to the Alliant Energy Corporation 401(k) Savings Plan.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Total Compensation Committee, which administers the Plan, has duly caused this Annual Report to be signed on its behalf by the undersigned, thereunto duly authorized, on this 27th day of June 2018.



	ALLIANT ENERGY CORPORATION
	401(k) SAVINGS PLAN

	/s/ Reuben P. Srinivasan
	Reuben P. Srinivasan

	The foregoing person is a Vice President
	of Alliant Energy Corporation and
	Alliant Energy Corporate Services, Inc., and the
	Chairperson of the Alliant Energy Corporation
	Total Compensation Committee.

EXHIBIT INDEX TO ANNUAL REPORT ON FORM 11-K

ALLIANT ENERGY CORPORATION

401(k) SAVINGS PLAN

FOR THE YEAR ENDED DECEMBER 31, 2017



Exhibit No.	Exhibit	Page Number in Sequentially Numbered Form 11-K
23	Consent of Independent Registered Public Accounting Firm	15