Annual Report of Employee Stock Purchase/Savings Plan Form 11 K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 11-K

(Mark One)

[X] ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the year ended December 31, 2023

OR

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

For the transition period from ____ to ____

Commission file number 333-179701, 333-82306, 333-115028, 333-135128, 333-156242, and 333-233037

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

Employees' Thrift Plan of Indianapolis Power & Light Company

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

The AES Corporation

4300 Wilson Boulevard

Suite 1100

Arlington, VA 22203

REQUIRED INFORMATION

A list of the required financial statements filed as part of this Form 11-K is set forth on page F-1. The consent of Ernst & Young to the incorporation by reference of these financial statements into the AES Corporation's Forms S-8 Registration Statements relating to the Plan (Registration No's. 333-179701, 333-82306, 333-115028, 333-135128, and 333-156242) is set forth hereto as Exhibit 23.1. The certification of the chief executive officer and the chief financial officer of Indianapolis Power & Light Company, which does business as AES Indiana, pursuant to 18 U.S.C. 1350, is attached hereto as Exhibit 99.1.

FINANCIAL STATEMENTS AND SUPPLEMENTAL

SCHEDULE

Employees' Thrift Plan of Indianapolis

Power & Light Company

December 31, 2023 and 2022,

and Year Ended December 31, 2023

With Report of Independent Registered Public Accounting Firm

Employees' Thrift Plan of Indianapolis Power & Light Company

Financial Statements and Supplemental Schedule

December 31, 2023 and 2022, and Year Ended December 31, 2023

Contents
Report of Independent Registered Public Accounting Firm	1
Financial Statements
Statements of Net Assets Available for Benefits	3
Statement of Changes in Net Assets Available for Benefits	4
Notes to Financial Statements	5
Supplemental Schedule
Schedule H, Line 4i - Schedule of Assets (Held at End of Year)	14

Report of Independent Registered Public Accounting Firm

To the Plan Participants and the Plan Administrator (the Employees' Pension and Benefits Committee) of the Employees' Thrift Plan of Indianapolis Power & Light Company

Opinion on the Financial Statements

We have audited the accompanying statements of net assets available for benefits of the Employees' Thrift Plan of Indianapolis Power & Light Company (the Plan) as of December 31, 2023 and 2022, and the related statement of changes in net assets available for benefits for the year ended December 31, 2023, 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 at December 31, 2023 and 2022, and the changes in its net assets available for benefits for the year ended December 31, 2023, in conformity with U.S. generally accepted accounting principles.

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. The Plan is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Plan's internal control over financial reporting. Accordingly, we express no such opinion.

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.

Supplemental Schedules Required by ERISA

The accompanying supplemental schedule of assets (held at end of year) as of December 31, 2023 (referred to as the "supplemental schedule"), has been subjected to audit procedures performed in conjunction with the audit of the Plan's financial statements. The information in the supplemental schedule is the responsibility of the Plan's management. Our audit procedures included determining whether the information 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

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forming our opinion on the information, we evaluated whether such information, including its form and content, is presented in conformity 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, the information is fairly stated, in all material respects, in relation to the financial statements as a whole.

/s/ ERNST & YOUNG LLP

We have served as the Plan's auditor since 2008

Indianapolis, Indiana

June 27, 2024

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Employees' Thrift Plan of Indianapolis Power & Light Company

Statements of Net Assets Available for Benefits

December 31,
2023	2022
Assets
Investments - at fair value	$	193,492,776	$	177,237,853
Receivables:
Notes receivable from participants	3,602,348	3,469,829
Participant contributions	301,605	287,025
Employer contributions	450,834	372,178
Total receivables	4,354,787	4,129,032
Total assets	197,847,563	181,366,885
Net assets available for benefits	$	197,847,563	$	181,366,885
See accompanying notes to financial statements.

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Employees' Thrift Plan of Indianapolis Power & Light Company

Statement of Changes in Net Assets Available for Benefits

Year Ended December 31, 2023

Additions
Investment income:
Interest and dividends	$	1,874,868
Interest income on notes receivable from participants	215,650
Contributions:
Participants	7,413,640
Rollovers	88,651
Employer	3,720,625
11,222,916
Net appreciation in fair value of investments	21,121,228
Total additions	34,434,662
Deductions
Benefit payments	21,556,984
Administrative expenses	123,044
Total deductions	21,680,028
Net increase before transfers	12,754,634
Plan Transfers	3,726,044
Net assets available for benefits:
Beginning of year	181,366,885
End of year	$	197,847,563
See accompanying notes to financial statements.

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1. Description of the Plan

The following description of the Employees' Thrift Plan of Indianapolis Power & Light Company (the Plan) provides general information about the Plan's provisions. Indianapolis Power & Light Company (the Company), which does business as AES Indiana, is the plan sponsor. AES Indiana is a subsidiary of The AES Corporation ("AES"). Participants should refer to the plan document and summary plan description, copies of which may be obtained from the plan sponsor, for a more complete description of the Plan's provisions.

General

The Plan is administered by the Employees' Pension and Benefits Committee (the Pension Committee), which is a committee as appointed from time to time by the Company's Board of Directors. The Plan is a defined contribution plan, and certain employees become eligible to participate in the Plan immediately upon date of employment. Eligible participants are automatically enrolled in the Plan after 30 days unless they affirmatively decline to participate. The Plan's trustee and record-keeper of the Plan's assets is T. Rowe Price Trust Company (T. Rowe Price). The Plan is subject to the provisions of the Employee Retirement Income Security Act of 1974, as amended (ERISA).

Contributions

Employee contributions are made through payroll deductions representing amounts equal to a specific percentage of the employee's base rate of compensation. Participants may also contribute amounts representing distributions from other qualified plans (rollover contributions). Employees have the option of contributing anywhere from 1% to 85% of base compensation, in increments of 1%, and direct their contributions into any of the investment options provided by the Plan. Employees can make such contributions under a "Before Tax" or "After Tax" option. If automatically enrolled, a participant's deferral is set to 4% of eligible compensation until changed by the participant. Participants who are automatically enrolled have their contributions invested in the applicable lifecycle fund based on their age until they change their election. Employer-matching contributions are made in an amount equal to current employee contributions up to a maximum of 5% for certain union employees; and 4% for other eligible employees. These employer-matching contributions are invested in the same funds the employee elects to have his/her contributions invested in. Certain union employees are also eligible to receive an annual lump-sum company contribution at the discretion of the plan sponsor's president. Annual lump-sum contributions of $291,933 and $241,010 were made in 2023 and 2022, respectively. Participants who have attained age 50 before the end of the year are eligible to make catch-up contributions. All contributions are subject to certain limitations of the Internal Revenue Code (the Code).

Participant Accounts

Each participant's account is credited with the participant's contribution, the Company's matching contribution, and any additional employer contributions as provided under the Plan. Participants have

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the option of investing their contributions in one or any combination of the available funds, which includes a self-directed brokerage account. Allocations of the Plan's earnings and losses are based on individual account balances relative to total account balances as of the valuation dates. Participant fund transfers are subject to certain restrictions as outlined in the summary plan description. In the event of partial or total termination of the Plan, the funds in the Plan shall be valued as of the date of partial or total termination and, after payment of necessary expenses, shall be distributed as though all participants directly affected by the partial or total termination had retired as of that date.

Vesting

Employee before and after-tax contributions are non-forfeitable and fully vested at all times. All eligible employees (including union and nonunion employees) vest at a rate of 20% per year and become fully vested in the Plan after five years of uninterrupted service related to employer contributions.

Employee Stock Ownership Plan

The portion of the Plan invested in AES common stock is intended to be an employee stock ownership plan (ESOP) within the meaning of Section 4975(e)(7) of the Code. Under the ESOP provisions, participants have the option to either receive, in cash, the distribution of dividends from AES or to reinvest the dividends in AES common stock. Effective March 1, 2018, the AES Common Stock investment option is closed to future contributions.

Forfeitures

Termination of employment before the five-year vesting term requires forfeiture of a prorated amount of allocated employer contributions. Forfeited amounts may be used to reduce employer-matching contributions or pay administrative expenses of the plan. Unallocated forfeiture balances as of December 31, 2023 and 2022, were $41,104 and $21,357, respectively, and forfeitures used to reduce employer contributions for 2023 and 2022 were $14,648 and $0, respectively.

Payment of Benefits

Upon separation from service with the Company due to death, disability, retirement, or termination, a participant, or the participant's beneficiary, may elect to receive either a lump-sum distribution, or elect an automatic rollover to an individual retirement account, or the participant has the option to maintain the account until required minimum distributions are mandatory; however, all distributions must be made in one lump-sum payment unless the participant has met his/her "required beginning date" allowing the participant to take annual installments of distributions. For a participant whose vested account balance is less than $5,000, the Plan makes an automatic rollover to an IRA with T Rowe Price on the participant's behalf if the participant fails to elect a direct rollover or to receive a cash lump sum payment.

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In-service withdrawals are available in certain limited circumstances, as defined by the Plan. Hardship withdrawals are allowed for participants incurring an immediate and heavy financial need, as defined by the Plan. Hardship withdrawals are strictly regulated by the Internal Revenue Service (the IRS).

Plan Assets

Assets of the Plan are maintained in trust. Once placed in trust, assets may be withdrawn only for the purpose of in-service, hardship, or age 59½ withdrawals by active employees; paying distributions to retiring employees; refunding employee contributions; payment of vested employer contributions to employees withdrawing from the Plan; payment of loan proceeds to participants electing a loan from the Plan; distributions to beneficiaries of deceased employees; or payment of the expenses of the Plan. Participants make requests for distributions directly with the record-keeper except for certain loans and refunds of participant contributions, which require approval from the Benefits Department of the Company. The Payroll and Benefits Departments of the Company conduct day-to-day activities of the Plan at the designation of the Pension Committee.

Administrative Expenses

The Plan's administrative expenses are paid by either the Plan or the Company, as provided by the Plan's provisions. Administrative expenses paid by the Plan include recordkeeping and trustee fees. Expenses relating to purchases, sales, or transfers of the Plan's investments are charged to the particular investment fund to which the expenses relate. All other administrative expenses of the Plan are paid by the Company. Expenses that are paid by the Company are excluded from these financial statements. Most permittable plan expenses are paid by plan participants.

Participant Loans

Participants may borrow up to the lesser of 50% of the vested portion of their account or $50,000, with a minimum loan requirement of $1,000. The available loan amount is reduced by the highest outstanding loan balance during the one-year period preceding the date the loan is made. The period of repayment of the loan can vary but generally will not exceed five years, except for loans used to purchase or construct a principal residence where the repayment period will not exceed ten years. The loans are secured by the balance in the participant's account and bear interest at 1% over prime. Principal and interest are normally paid through payroll deductions. Plan participants have the ability to pay off their loans at any time directly with the Plan's record-keeper. Participants who separate from service with a loan balance outstanding have the option to either pay off their loan or make monthly payment arrangements directly with the Plan's record-keeper. Once participants have separated from service, they are prohibited from taking out any new loans. A participant may not have more than four loans outstanding at any point in time.

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Plan Termination

Although it has not expressed any intent to do so, the Company has the right under the Plan to discontinue its contributions at any time and to terminate the Plan subject to the provisions of ERISA. In the event of plan termination, participants would become 100% vested in their employer contributions.

Plan Amendments and Transfers

Effective January 1, 2022, the Plan was amended to allow plan-to-plan transfers with respect to certain employees who transfer employment within the Company. During 2023, the total of plan assets transferred into and out of the plan were $4,746,213 and $1,020,169 respectively.

2. Summary of Significant Accounting Policies

Basis of Accounting

The accompanying financial statements of the Plan have been prepared on the accrual basis of accounting.

Payment of Benefits

Benefits are recorded when paid.

Notes Receivable from Participants

Notes receivable from participants represent participant loans that are recorded at their unpaid principal balance plus any accrued but unpaid interest. Interest income on notes receivable from participants is recorded when it is earned. Related fees are recorded as administrative expenses and are expensed when they are incurred. No allowance for credit losses has been recorded as of December 31, 2023 or 2022. If a participant ceases to make loan repayments and the plan administrator deems the participant loan to be a distribution, the participant loan balance is reduced, and a benefit payment is recorded.

Use of Estimates

The preparation of financial statements in conformity with United States generally accepted accounting principles requires management to make estimates that affect amounts reported in the financial statements and accompanying notes and supplemental schedule. Actual results could differ from those estimates.

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Investment Valuation and Income Recognition

Investments held by the Plan are stated at fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (an exit price). See Note 3 for further discussion of fair value measurements.

Purchases and sales of securities are recorded on a trade-date basis. Interest income is recorded as earned. Dividends are recorded on the ex-dividend date. Net appreciation includes the Plan's gains and losses on investments bought and sold, as well as held, during the year.

3. Fair Value Measurements

The fair value framework establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The fair value hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets and liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). The three levels of the fair value hierarchy are described below:

•Level 1 - Quoted prices in active market for identical assets.

•Level 2 - Significant observable inputs. Level 2 inputs include the following:

•quoted prices for similar assets and liabilities in active markets;

•quoted prices for identical or similar assets or liabilities in markets that are not active;

•observable inputs other than quoted prices that are used in the valuation of the assets or liabilities (e.g., interest rate and yield curve quotes at commonly quoted intervals);

•inputs that are derived principally from or corroborated by observable market data by correlation or other means.

•Level 3 - Unobservable inputs for the asset or liability (i.e., supported by little or no market activity). Level 3 inputs include management assumptions regarding market participant assumptions used in pricing the asset or liability (including assumptions about risk).

The level in the fair value hierarchy within which the fair value measurement is classified is determined based on the lowest level input that is significant to the fair value measurement in its entirety.

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Following is a description of the valuation techniques and inputs used for each general type of investments measured at fair value by the Plan:

AES Common Stock: AES common stock is valued at the closing price reported on the active market on which AES common stock is traded.

Mutual Funds: Mutual funds, including money market funds, are valued at quoted market prices that represent the net asset value of shares held by the Plan at year-end.

Common/Collective Trusts (CCTs): Valued at net asset value provided by the administrator of the funds.

Self-Directed Brokerage Account: Consists of mutual funds which are valued at quoted market prices that represent the net asset value of shares; collective trusts which are valued at net asset value provided by the plan administrators and common stocks which are valued at the closing price reported on the active market where it is traded.

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.

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The following tables set forth by level, within the fair value hierarchy, the Plan's assets carried at fair value:

Fair Value Measurements at December 31, 2023
Level 1	Level 2	Level 3	Total
AES common stock	$	8,974,861	$	-	$	-	$	8,974,861
Money market funds	5,677,575	-	-	5,677,575
Mutual funds	17,877,364	-	-	17,877,364
Self-directed investments	2,912,111	-	-	2,912,111
Collective investment trusts	158,050,865	-	-	158,050,865
Total assets at fair value	$	193,492,776	$	-	$	-	$	193,492,776
Fair Value Measurements at December 31, 2022
Level 1	Level 2	Level 3	Total
AES common stock	$	14,045,114	$	-	$	-	$	14,045,114
Money market funds	5,900,004	-	-	5,900,004
Mutual funds	14,173,291	-	-	14,173,291
Self-directed investments	2,077,053	-	-	2,077,053
Collective investment trusts	141,042,391	-	-	141,042,391
Total assets at fair value	$	177,237,853	$	-	$	-	$	177,237,853

4. Related Party and Party-in-Interest Transaction

One of the Plan's investment options is AES common stock. Since AES is the parent company of IPALCO Enterprises, Inc. and IPALCO Enterprises, Inc. is the parent company of the Company, all investment transactions involving AES common stock qualify as party-in-interest transactions. However, the transactions are exempt from the prohibited transactions rules under ERISA. During 2023 and 2022, the Plan received $301,925 and $309,393 in common stock dividends from AES, respectively.

Certain Plan investments are shares of mutual funds and units of common/collective trust funds managed by T. Rowe Price. T. Rowe Price is the Trustee as defined by the Plan. These transactions qualify as party-in-interest transactions; however, they are exempt from the prohibited transaction rules under ERISA.

T. Rowe Price provides certain administrative services to the Plan pursuant to a Master Plan Services Agreement (MSA) between the Company and T. Rowe Price. T. Rowe Price receives revenue from mutual fund and collective trust fund service providers for services T. Rowe Price provides to the

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funds. This revenue is used to offset certain amounts owed to T. Rowe Price for its administrative services provided to the Plan.

If the revenue received by T. Rowe Price from such mutual fund or collective trust fund service providers exceeds the amount owed under the MSA, T. Rowe Price remits the excess to the Plan's trust on a quarterly basis. Such amounts may be applied to pay plan administrative expenses or allocated to the accounts of participants. During 2023 and 2022, $67,573 and $39,760, respectively, was remitted to the Plan's trust. The Plan or the Company may make a payment to T. Rowe Price for administrative expenses not covered by sharing of the excess revenue.

5. Risks and Uncertainties

The Plan invests in various investment securities. Investment securities are exposed to various risks, such as interest rate, market volatility, and credit risks. Due to the level of risk associated with certain investment securities, it is at least reasonably possible that changes in the values of investment securities will occur in the near term and that such changes could materially affect participants' account balances and the amounts reported in the statements of net assets available for benefits.

6. Tax Status

The Plan has received a determination letter from the IRS dated August 17, 2017 stating that the Plan is qualified under Section 401(a) of the Code and, therefore, the related trust is exempt from taxation. Subsequent to this determination by the IRS, the Plan was amended and restated. Once qualified, the Plan is required to operate in conformity with the Code to maintain its qualified status. The plan administrator believes the Plan is being operated in compliance with the applicable requirements of the Code and, therefore, believes the Plan, as amended and restated, is qualified and the related trust is tax-exempt.

Accounting principles generally accepted in the United States require plan management to evaluate tax positions taken by the Plan and recognize a tax liability if the Plan has taken an uncertain tax position that more likely than not would not be sustained by examination by the IRS. Plan management has analyzed the tax positions taken by the Plan and has concluded there are no uncertain tax positions taken or expected to be taken. The Plan is subject to routine audits by taxing jurisdictions; however, there are currently no audits for any tax periods in progress.

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Supplemental Schedule

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Employees' Thrift Plan of Indianapolis Power & Light Company

Schedule H, Line 4i - Schedule of Assets

(Held at End of Year)

EIN 35-0413620 Plan #003

December 31, 2023

Party-in-interest	Identity of Issue, Borrower, Lessor, or Similar Party	Description of Investment, Including Maturity Date, Rate of Interest, Collateral, Par, or Maturity Value	Cost	Current Value
(a)	(b)	(c)	(d)	(e)
Money Market Mutual Funds:
*	T. Rowe Price Trust Company	TRP Government Money Market Fund	42,189	**	42,189
Vanguard	Vanguard Fed Money Market Fund	5,635,386	**	5,635,386
Total Money Market Mutual Funds	5,677,575
Mutual Funds:
American Funds	American EuroPacific Growth Fund	36,261	**	1,967,141
American Funds	American Washington Mutual Investment	80,127	**	4,572,847
*	T. Rowe Price Trust Company	Blue Chip Growth Fund	64,422	**	9,620,855
Metropolitan West Funds	Met West Total Return Bond Fund	186,578	**	1,716,521
Total Mutual Funds	17,877,364
Common/Collective Trusts:
JP Morgan	Small Cap Equity RS	10,615	**	575,815
State Street Global Advisors	State St US Bond Index Fund	100,125	**	1,063,026
State Street Global Advisors	State St Russell Sm/Mid Cap Index Fund CL II	247,985	**	3,897,330
State Street Global Advisors	State Street S&P 500 Index Fund Class II	486,741	**	10,078,451
State Street Global Advisors	State St Gbl All Cp EQ ex-US IdxSL CI II	16,713	**	222,380
*	T. Rowe Price Trust Company	TRP Stable Value Fund - N	14,639,063	**	14,639,063
*	T. Rowe Price Trust Company	Retirement 2005 TR Fund	39,478	**	763,503
*	T. Rowe Price Trust Company	Retirement 2010 TR Fund	17,672	**	363,523
*	T. Rowe Price Trust Company	Retirement 2015 TR Fund	276,251	**	6,193,549
*	T. Rowe Price Trust Company	Retirement 2020 TR Fund	573,369	**	13,938,597
*	T. Rowe Price Trust Company	Retirement 2025 TR Fund	1,005,471	**	26,554,490
*	T. Rowe Price Trust Company	Retirement 2030 TR Fund	1,044,659	**	29,814,563
*	T. Rowe Price Trust Company	Retirement 2035 TR Fund	529,942	**	16,147,322
*	T. Rowe Price Trust Company	Retirement 2040 TR Fund	324,798	**	10,390,289
*	T. Rowe Price Trust Company	Retirement 2045 TR Fund	248,363	**	8,133,879
*	T. Rowe Price Trust Company	Retirement 2050 TR Fund	194,626	**	6,385,663
*	T. Rowe Price Trust Company	Retirement 2055 TR Fund	133,730	**	4,384,992
*	T. Rowe Price Trust Company	Retirement 2060 TR Fund	170,395	**	3,574,888
*	T. Rowe Price Trust Company	Retirement 2065 TR Fund	70,795	**	929,542
Total Common/Collective Trusts	158,050,865
Stock:
*	The AES Corporation	The AES Corporation Common Stock	466,227	**	8,974,861
Self-Directed Brokerage:
Charles Schwab	Self-Directed Brokerage Mutual Funds	-	**	2,912,111
Notes Receivable from Participants:
Participant Loans	Interest rates from 4.25% to 8.50% with various maturities through July 2032	3,602,348
Total	$	197,095,124
* Party-in-interest.
** Participant directed investment, cost not required.

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