United States

Securities and exchange commission
washington, d.c. 20549

FORM 6-K

report of foreign private issuer
pursuant to rule 13a-16 or 15d-16 of
the securities exchange act of 1934

For the month of January 2026

Commission File Number 1-15224

Energy Company of Minas Gerais

(Translation of Registrant’s Name into English)

Avenida Barbacena, 1200

30190-131 Belo Horizonte, Minas Gerais, Brazil

(Address of Principal Executive Offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F   a  Form 40-F ___ 

Index

Forward-Looking Statements

This report contains statements about expected future events and financial results that are forward-looking and subject to risks and uncertainties. Actual results could differ materially from those predicted in such forward-looking statements. Factors which may cause actual results to differ materially from those discussed herein include those risk factors set forth in our most recent Annual Report on Form 20-F filed with the Securities and Exchange Commission. CEMIG undertakes no obligation to revise these forward-looking statements to reflect events or circumstances after the date hereof, and claims the protection of the safe harbor for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG

By: /s/ Andrea Marques de Almeida .

Name: Andrea Marques de Almeida

Title: Vice President of Finance and Investor Relations

Date: January 20, 2026

COMPANHIA ENERGÉTICA DE MINAS GERAIS - CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

MATERIAL FACT

Collective Bargaining Agreement Regarding Health Plans

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“CEMIG” or “Company”), a publicly-held company with shares traded on the stock exchanges of São Paulo and New York, hereby informs its shareholders and the market in general, under CVM Resolution 44/2021, that, in continuity to the Material Fact disclosed on February 20, 2025, it has filed, on September 11, 2025, in the records of the collective bargaining dispute Process 0011802-15.2025.5.03.0000, the agreement signed with labor unions SINDSUL – Sindicato dos Eletricitários do Sul de Minas Gerais and FTIUMG – Federação dos Trabalhadores nas Indústrias Urbanas de Minas Gerais.

The agreement establishes a buyout payment for compensatory damages in a maximum total amount of R$1,250,000,000.00 (one billion, two hundred and fifty million reais), to be paid pro rata in 6 (six) installments, the last one in 2030, relating to 15,496 (fifteen thousand, four hundred and ninety-six) retirees and pensioners, all of whom were active and enrolled in the CEMIG Saúde PSI health plan in February 2025.

The agreement, which is subject to approval by the Regional Labor Court of the 3rd Region, is resolutory in nature and applies to those who are represented or affiliated with the signing entities, as well as those who may subsequently adhere to them.

CEMIG reaffirms its commitment to keeping shareholders and the market in general informed about this matter, under CVM regulations and the applicable legislation.

Belo Horizonte, September 12, 2025.

Andrea Marques de Almeida

Vice President of Finance and Investor Relations

COMPANHIA ENERGÉTICA DE MINAS GERAIS - CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

MATERIAL FACT

Collective Bargaining Agreement Regarding Health Plans

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“CEMIG” or “Company”), a publicly-held company with shares traded on the stock exchanges of São Paulo and New York, hereby informs its shareholders and the market in general, under CVM Resolution 44/2021, that, in continuity to the Material Facts disclosed on September 12, 2025, and February 20, 2025, the collective bargaining dispute proceeding filed under Process 0011802-15.2025.5.03.0000 was approved today and an agreement has been signed with labor unions SINDSUL – Sindicato dos Eletricitários do Sul de Minas Gerais and FTIUMG – Federação dos Trabalhadores nas Indústrias Urbanas de Minas Gerais.

The agreement establishes a buyout payment for compensatory damages in a maximum total amount of R$1,250,000,000.00 (one billion, two hundred and fifty million reais), to be paid pro rata in 6 (six) installments, the last one in 2030, relating to 15,496 (fifteen thousand, four hundred and ninety-six) retirees and pensioners, all of whom were active and enrolled in the CEMIG Saúde PSI health plan in February 2025. The Company remains committed to signing agreements with the remaining labor unions.

CEMIG reaffirms its commitment to keeping shareholders and the market in general informed about this matter, under CVM regulations and the applicable legislation.

Belo Horizonte, September 19, 2025.

Cristiana Maria Fortini Pinto e Silva

Acting Vice President of Finance and Investor Relations

COMPANHIA ENERGÉTICA DE MINAS GERAIS - CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

MATERIAL FACT

Direct Action of Unconstitutionality 7,324

Amounts to be refunded to consumers

A COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“CEMIG” or “Company”), a publicly-held company with shares traded on the stock exchanges of São Paulo and New York, hereby informs its shareholders and the market in general, under CVM Resolution 44/2021, that, on August 14, 2025, the Brazilian Federal Supreme Court (STF) ruled, within the scope of Direct Action of Unconstitutionality Number 7,324, on the constitutionality of Law 14,385/2022, which regulates the refund to electricity consumers of tax amounts overpaid by distribution companies.

The Company is awaiting the publication of the court ruling to assess the potential accounting, financial, and operational impacts arising from the decision.

CEMIG reaffirms its commitment to keeping shareholders and the market in general informed about this matter, under CVM regulations and the applicable legislation.

Belo Horizonte, August 14, 2025.

Andrea Marques de Almeida

Vice President of Finance and Investor Relations

EBITDA AND PROFIT BY COMPANY, 3Q25 AND 3Q24

"More details on the Transmission regulatory result can be found in the section Transmission: Regulatory Revenue and Ebitda. 

CEMIG: P&L, 3Q25 AND 3Q24

RESULTS BY BUSINESS SEGMENT

CONSOLIDATED ELECTRICITY MARKET

Cemig’s consolidated electricity market

In September 2025 the Cemig Group invoiced approximately 9.55 million clients – an increase of approximately 203,000 clients, or 2.2%, in its consumer base since the end of September 2024. Of this total number of consumers, 9,547,888 are final consumers, and/or represent Cemig’s own consumption; and 622 are other agents in the Brazilian electricity sector.

This chart shows the Cemig Group’s sales to final consumers by segment:

PERFORMANCE BY COMPANY

Cemig D

Billed electricity market

* Excludes supply compensated in Distributed Generation.

Electricity billed to captive clients plus transport of energy for Free Clients and distributors, excluding supply offset in distributed generation, totaled 11,834 GWh in 3Q25 – 4.4% less than in 3Q24. This was mainly the result of lower consumption by industrial clients (down 476.0 GWh, or 8.0%, year-on-year), rural clients (–71.1 GWh or –7.6%), commercial clients (–48.0 GWh or –3.4%), and public services (–27.5 GWh or –3.4%), mainly reflecting migration of clients to Distributed Generation and to the Free Market. On the other hand, consumption by residential clients was 83.1 GWh (+2.7%) higher than in 3Q24.

The year-on-year reduction of 4.4% in total energy distributed comprised: a reduction of 6.1% (354.0 GWh) in consumption by the captive market, and a reduction of 2.9% (189.3 GWh) in use of the network by Free Clients. Taking distributed generation offset energy into account, total distributed energy was 2.0% lower than in 3Q24.

Energy distributed, by segment (%)

Distribution – volume sold, by consumer sector

Industrial: Energy distributed to/for industrial clients was 8.0% less than in 3Q24, and was 46.4% of the total volume distributed by Cemig D. A large proportion was energy transported for industrial Free Clients (45.0%), which in total was 6.6% lower in volume than in 3Q25. Within the total, energy billed to captive industrial clients was 1.4% of the total distributed, and 37.7% less by volume than in 3Q24 – mainly due to migration of clients to the Free Market.

A strong impact on this reduction in industrial consumption came from migration of two major clients to the Free Market. Without this effect the year-on-year reduction in total energy distributed would have been 3.1%. Sectors with lower consumption in 3Q25 were primarily: steel, down 36.9%YoY, chemicals (down 27.9%), and ferro-alloys (down 10.4%). Consumption was higher, YoY, in extractive industries (up 3.3%), the auto industry (up 3.5%) and foods and beverages (up 1.1%).

Residential consumption was 26.5% of the total energy distributed by Cemig D in the quarter, and 2.7% higher by volume than in 3Q24. Average monthly consumption per consumer (128.3 kWh/month) was 0.4% lower than in 3Q24. On the other hand, the total number of residential clients grew by 3.1% year-on-year (Cemig D added a significant total of 200,400 new clients in the 12-month period).

Commercial and Services: Energy distributed to these consumers was 12.4% of the total distributed by Cemig D in 3Q25, and by volume 3.2% less than in 3Q24. The change has two components: (i) energy billed to captive clients 14.9% lower; and (ii) volume transported for Free Clients 15.6% higher – reflecting migration of clients to the Free Market. The lower figure for total consumption mainly reflects migration of clients to distributed generation.

Rural: This sector received 7.3% of the energy distributed by Cemig D – totaling 7.6% less by volume than in 3Q24, mainly due to a 4.0% reduction in the number of consumer units, of which a large proportion were reclassified to the residential category.

Public services: consumed 6.6% of the energy distributed in the quarter, 3.4% less by volume than in 3Q24.

Sources and uses of electricity – MWh

Client base

In September 2025 Cemig billed 9.54 million consumers, or 2.2% more than in September 2024. Of this total, 5,907 were Free Clients using the distribution network of Cemig D.

The 2025 Annual Tariff Adjustment

Cemig D’s tariffs are re-set in May each year; and every five years are subjected to a Periodic Tariff Review, also in May. The purposes of the Annual Adjustment are: (i) to pass on to the client, in full, changes in the costs defined as “non-manageable”; and (ii) to provide inflation adjustment for the costs which are specified in the Tariff Review as “manageable”. Manageable costs are adjusted by the IPCA inflation index, less a factor known as the ‘X Factor’, designed to capture productivity, under a system using a price-cap regulatory model.

Aneel (the Brazilian electricity regulator) ratified Cemig D’s last annual Tariff Adjustment on May 20, 2025, to be effective from May 28, 2025 to May 27, 2026. It resulted in an average increase, for consumers, of 7.78%. The average effect for low-voltage consumers was an increase of 7.03%, and for residential consumers, an increase of 6.86%. The component percentage of the increase corresponding to manageable costs (referred to as ‘Portion B’) was 1.36%. The increase relating to non-manageable costs (‘Portion A’ – comprising purchase of energy, transmission, sector charges and non-recoverable revenues) was 6.12%. The increase in the financial components of the tariff contributed 0.30 percentage points. The item with the greatest impact on the tariff increase was the sector charges, which contributed an effect of 4.63%, reflecting an increase in the CDE (the Energy Development Account, a government sector charge).

More details at this link:

https://www2.aneel.gov.br/aplicacoes/tarifa/arquivo/SEI_0111327_Nota_Tecnica_116_Cemig.pdf

Five-year Tariff Reviews compared

Comparison of the Tariff Reviews made in 2023 and in the previous cycle (2018):

* CAIMI: (Cobertura Anual de Instalações Móveis e Imóveis) – Annual support for facilities.

* QRR: ‘Regulatory Reintegration Quota’: Gross base x annual depreciation rate.

See more details at this link: https://www2.aneel.gov.br/aplicacoes/tarifa/arquivo/NT%2012%202023%20RTP%20Cemig.pdf

Opex and Ebitda: Realized vs. Regulatory

Realized Opex and Ebitda were both better than regulatory levels in 9M25:

R$ million

Regulatory Ebitda is calculated by reference to: (i) remuneration of capital; (ii) the QRR quota (Gross base x annual depreciation rate); and (iii) a percentage of the Annual Cost of Facilities and Real Estate, published in Aneel Technical Notes at the times of Tariff Reviews and Tariff Adjustments.

Supply quality indicators – DEC and FEC

Cemig’s DEC (Average Outage Duration) for the 12 months to end-September 2025, at 9.34 hours, was again within the regulatory limit of 9.48 hours (down from 9.76 hours in the 12 months to end-June). Its Average Outage Frequency indicator (FEC) for the same 12 months was 5.25, within the regulatory parameter, of 5.83 per year (down from 5.37 at end-June 2025).

Combating default

The Company has maintained a high level of collection actions, helping to keep the Receivables Recovery Index high – it was 99.09% in September 2025.

Collection of customer invoices via digital channels (Brazil’s PIX instant payment system, automatic monthly debit, payment by credit card, various apps, etc.) was 68.09% of all receivables collected – or 0.409 pp higher than in 3Q24. PIX was the method most used by clients – for a total of 33.4% of the total of all collection – providing savings of R$ 35.0 million in collection expenses since it was put in place in 2021.

Energy losses

Energy losses in the 12 months to September 2025, at 11.42%, were below the regulatory minimum of 11.47%. Aneel Technical Note 53/2025 specified an updated method for calculation of non-technical losses, in effect as from May 28, 2025 (date of the most recent tariff adjustment): this update now considers the measured energy from distributed generation (DG) in the calculation, rather than billed energy.

Some main features of our combat of energy losses in 9M25 were:

For full-year 2025, a total of 340,000 inspections are planned, with replacement of 425,000 obsolete meters, and installation of external meters where consumers have repeatedly tried to achieve irregular consumption.

Cemig GT and Cemig holding company

Electricity market

The total volume of electricity sold in 3Q25 by Cemig GT and by the holding company (Cemig H’), excluding sales on the wholesale power exchange (CCEE), was 16.8% higher than in 3Q24.

Cemig GT billed 6,438 GWh (including quota sales) in 3Q25, 25.6% more than in 3Q25.

The holding company reported sales of 5,122 GWh in 3Q25, 7.3% more than in 3Q24. Migration of energy purchase contracts from Cemig GT to ‘Cemig H’ was begun in 3Q21, has continued gradually since then, and is now around 61%.

Of the total sold by the holding company and Cemig GT in 3Q25, sales in the ‘retail market’ in the quarter accounted for 383.5 GWh.

Sources and uses of electricity

Gasmig

Gasmig, 99.57% owned by Cemig, is the exclusive distributor of piped natural gas for the whole of Minas Gerais State. It supplies industrial, commercial and residential users, users of compressed natural gas and vehicle natural gas, and gas as fuel for thermoelectric generation plants. Its concession expires in January 2053.

Gasmig’s last Tariff Review was completed in April 2022. Highlights of that review:

Total volume of gas distributed in 3Q25 was 5.6% lower than in 3Q24: captive market sales were 54.5% (120,600m³) lower than in 3Q24, and volume distributed to industrial and thermoelectric generation Free Clients was 196.6% (105,400 m³) higher. The main factor in these changes was migration of industrial clients to the Free Market, increasing the volume sold to that market. In terms of total volume distributed, industrial clients showed the largest reduction: approximately 13,000 m³, compared to 3Q24.

Gasmig’s 3Q25 Ebitda was 8.2% lower than in 3Q24, mainly due to the changes in volume of gas distribution to industrial clients.

Gasmig’s total number of clients increased by 6.8% from 3Q24, to a total of 108,682 consumers in 3Q25 – reflecting expansion of the commercial and the residential client bases (total addition of 6,100 clients).

CEMIG – Consolidated results

Net profit

Cemig reports 3Q25 net profit of R$ 796.7 million, which compares to net profit of R$ 3,280.2 million in 3Q24. Adjusted net profit for 3Q25 is R$ 780.2 million, compared to R$ 1,118.4 million in 3Q24. The main factors in this result were:

The prior year: Effects in 3Q24

More details on the variations in 3Q25 are given below.

Operational revenue

Revenue from supply of electricity

* Includes offset distributed generation.

Energy sold to final consumers

Gross revenue from energy sold to final consumers in 3Q25 was R$ 7,758.4 million, a 6.1% year-on-year increase from R$ 7,313.0 million in 3Q24, mainly reflecting volume of energy sold 4.1% higher.

Wholesale supply

Revenue from wholesale supply in 3Q25 was R$ 1,320.9 million, up 6.3% from R$ 1,243.1 million in 3Q24. Volume of energy invoiced was 24.6% higher, led by sales to Traders; average price was 12.0% lower.

Transmission

Cemig’s transmission revenue comprises: (i) Operating and maintenance revenue, (ii) Construction revenue, and (iii) financial compensation of the contractual asset. In 3Q25 it totaled R$ 289.7 million, 2.6% less than in 3Q24. This mainly reflected lower Operation and maintenance revenue; while Construction revenue was higher, due to the higher volume of funds invested in strengthening and improvement works.

Gas

Gross revenue from supply of gas in 3Q25 totaled R$ 614.0 million, compared to R$ 1,038.1 million in 3Q24. The main effect was migration of industrial clients to the Free Market and consequently lower volume sold.

Revenue from Use of Distribution Systems – the TUSD charge

In 3Q25 revenue from the TUSD – charged to Free Consumers for distribution of their energy – was R$ 139.6 million higher than in 3Q24. This reflects (i) the annual tariff adjustment of Cemig D, coming into effect in May 2025, and thus with full effect in this quarter, while (ii) total volume transported for Free Clients was lower.

Operational costs and expenses

Operating costs and expenses totaled R$ 9.54 billion in 3Q25, an increase of R$ 787.8 million compared to 3Q24 (after adjusting for items totaling R$ 3.15 billion included in 3Q24: R$ 1.62 billion on the sale of Aliança, and R$ 1.52 billion for the Transmission Periodic Tariff Review).

The increase reflects:

See more details on costs and expenses in the following pages.

Electricity bought for resale

The consolidated expense on electricity bought for resale in 3Q25 was R$ 5.16 billion, an increase of 13.0% (R$ 596.0 million) from 3Q24. This mainly reflects:

Note that for Cemig D, purchased energy is classified as a non-manageable cost: the difference between the amounts used as a reference for calculation of tariffs and the costs actually incurred is compensated for in the next tariff adjustment.

Charges for use of the transmission network and other system charges

Charges for use of the transmission network in 3Q25 were R$ 776.7 million, 4.8% lower than in 3Q24.

This is classified as a non-manageable cost in the distribution business: the difference between the amounts used as a reference for calculation of tariffs and the costs actually incurred is compensated for in the next tariff adjustment.

Gas purchased for resale

The expense on acquisition of gas in 3Q25 was R$ 240.9 million, or 55.7% less than in 3Q24 – reflecting lower total volume of gas purchased to meet demand from the Regulated Market, due to migration of important industrial customers to purchasing in the Free Market.

Outsourced services

Expenditure on outsourced services was 17.4% (R$ 86.7 million) higher than in 3Q24, with the following increases as the main factors: expenses on maintenance R$ 35.6 million (+21.0%) higher, led by increased preventive maintenance; expenses on information technology R$ 13.5 million (+38.7%) higher; expenses on tree pruning R$ 7.6 million (+33.6%) higher; and expenses on communication R$ 7.4 million (+16.9%) higher.

Provisions for client default

A provision of R$ 60.3 million was posted for losses on receivables in 3Q25, which compares to a reversal of R$ 50.6 million in 3Q24. This mainly arises from the change, in 3Q24, of the rules for provisioning unpaid receivables: extension of the time limit for 100% recognition of unpaid receivables from 24 to 36 months, to give a more accurate estimate of actual losses on overdue client bills in practice. This review had the effect of reducing the provision made in 3Q24 by R$ 93.0 million.

Provisions, Expected loss on other credits, and Reversal of provision for related-party loss

These 3 lines totaled R$ 126.0 million in 3Q25, compared to R$ 35 million in 3Q24. The main component is the reversal, in 3Q24, of a R$ 57.8 million provision for a related party transaction, arising from a contractual obligations with Aliança Geração: together with the sale of Cemig’s share in Aliança, an agreement was made for termination and settlement of this contingency.

Post-employment liabilities

An expense of R$ 105.30 million is posted in 3Q25 for Cemig’s post-retirement obligations, 13.7% less than in 3Q24 (R$ 122.0 million). The difference reflects reversal of R$ 22.6 million in 3Q25, due to migration of 530 employees to the new health plan, which creates no post-employment obligation for the Company.

Post-employment – Health Plans: Agreement in collective bargaining; Under a September 2025 agreement between Cemig and two unions – the South Minas Gerais Electricity Workers’ Union (Sindsul) and the Minas Gerais Federation of Urban Industry Workers (FTIUMG) – current active employees migrated to the Premium Health Plan, 100% funded by the Company, effective as of October 1, 2025. Negotiations with other unions and associations continue. In 3Q25, no accounting effect was recorded as a result of the ratified agreement, other than those arising from the migration of active employees. More details about the agreement can be found at the following link:

https://ri.cemig.com.br/docs/Cemig-2025-09-19-QQdHkwTC.pdf

People

The expense on personnel in 3Q25 was R$ 337.1 million, 3.4% more than in 3Q24. The main factor in the higher figure was the increase of 4.6% in salaries as from November 2024, under the Collective Work Agreement.

Finance income and expenses

For 3Q25 Cemig reports consolidated Net finance expenses of R$ 276.1 million, or R$ 214.5 million more than in 3Q24. Main factors in the comparison:

Equity income (Gain (loss) in non-consolidated investees)

The total of equity income was R$ 20.9 million lower in 3Q25 than 3Q24. The main effect was the improvement in the profit of Taesa, mainly due to the deflation of the IGP-M (index that adjusts part of the company’s contract asset) from June to August 2025 (with a one-month lag) while the result of Belo Monte was weaker, on higher finance expense (due to the higher TJLP in 3Q25).

CONSOLIDATED EBITDA (IFRS, and Adjusted)

Ebitda is a non-accounting metric, prepared by the Company, reconciled with its consolidated financial statements in accordance with the specifications in CVM Circular SNC/SEP 01/2007 and CVM Resolution 156 of June 23, 2022. It comprises: Net profit adjusted for the effects of: (i) Net finance income (expense), (ii) Depreciation and amortization, and (iii) Income tax and the Social Contribution tax. Ebitda is not a metric recognized by Brazilian GAAP nor by IFRS; it does not have a standard meaning; and it may be non-comparable with metrics with similar titles provided by other companies. Cemig publishes Ebitda because it uses it to measure its own performance. Ebitda should not be considered in isolation or as a substitute for net profit or operational profit, nor as an indicator of operational performance or cash flow, nor to measure liquidity, nor capacity for payment of debt. The Company adjusts its Ebitda (calculated in accordance with CVM Instruction 156/2022) to exclude extraordinary items which, by their nature, do not contribute to information on the potential for gross cash flow generation.

Ebitda (IFRS) was 69.7% lower than in 3Q24, mainly due to two positive effects in the prior year: a positive item of R$ 1,520.6 million from the Periodic Tariff Review of the Transmission operation, and a positive effect of R$ 1,674.7 million from the sale of the interest in Aliança Geração.

3Q25 Adjusted Ebitda was 16.3% lower year-on-year, mainly reflecting:

Cemig D – Ebitda

Cemig D posted 3Q25 Ebitda of R$ 758.5 million, 1.9% lower than in 3Q24. Adjusted Ebitda, at R$ 737.4 million), was 4.7% lower than in 3Q24.

Here are some of the main effects on Ebitda in the comparison of 3Q25 with 3Q24:

Cemig GT – Ebitda

Cemig GT reports 3Q25 Ebitda of R$ 529.7 million, and adjusted Ebitda of R$ 525.8 million, 12.7% less than in 3Q24. The main factors in the difference are:

Main factors in the prior year (result of 3Q24):

Investments

Capex in the first nine months of 2025 (9M25) totaled R$ 4.73 billion, 17.0% more than in 9M24. Investment realized in the quarter (3Q25) totaled R$ 1.98 billion.

Highlights of 9M25 – In these nine months Cemig has invested R$ 2.16 billion in distribution, including: ● connection of more than 140,000 new clients, ● 14 new substations (adding +205 MVA to the network); ● installation of a further 115,000 smart meters; ● investment of R$ 253 million in strengthening and enhancement of the transmission network; ● extension of the concession of 3 plants, with purchase of credits at the GSF auction (R$ 199 million); ● addition of 31 MWp of installed capacity in photovoltaic distributed generation; and ● construction by Gasmig of 151 km of gas pipelines.

This execution of the largest investment program in Cemig’s history will modernize its electricity system, ensuring reliability, in line with its strategic plan of focusing on Minas Gerais and on its core businesses, and providing ever-improving service to Cemig’s clients. Investment totaling R$ 39.20 billion is planned for the period 2025–29, of which R$ 6.35 billion is being invested in 2025.

Debt

In 3Q25:

(i) Cemig GT raised US$40 million, in a transaction with one-year maturity and a linked full swap.

(ii) Gasmig settled a total of R$ 95.0 million: the second amortization tranche of its 8th debenture issue.

Cemig’s long-term ratings

Cemig’s ratings have improved very significantly in recent years – and are now at their highest ever levels. The main news in 3Q25 was the upgrade to AAA by one more rating agency, this time Moody’s, in September.

(Cemig ratings – Background:)

●  In 2021 the three leading agencies upgraded their ratings for Cemig.

●  In April 2022, Moody’s made a further upgrade, by one notch.

●  In May 2024, Moody’s raised its rating to AA+.

●  In October 2024 Fitch raised its rating to AAA, the highest on its Brazilian scale, stating recognition of:

More details in this table:

ESG: Engagement and performance

Cemig has established public commitments in terms of sustainability – for which it executes strategic initiatives, monitored by corporate indicators and goals. These commitments subdivide into five key areas: (i) the energy transition, (ii) the environment, (iii) local development, (iv) our people and (v) solid governance.

Cemig ESG highlights

Energy Transition: highlight

In decarbonization – Cemig is making significant progress and can assert its leadership position.

It has already met its commitment to offset 100% of scope 1 emissions by 2026, in relation to the company’s 2024 inventory (the 2025 figures are yet to be finalized). Cemig companies will continue to offset their emissions in the coming years.

In distributed generation, evidencing its continuing major initiatives, Cemig has connected over 5.5 GW of distributed generation capacity – already well over half of its 2028 target of 7 GW.

Environment: highlight

Fulfilling a significant environmental commitment ahead of time, Cemig has completed the diagnosis of ecosystem services impacts and dependencies – which was scheduled for 2026.

Local development: highlight

Cemig contributes to local development with numerous projects that are beneficial to the public. One example is its commitment to benefit at least 60,000 people with projects for infancy, the elderly and sport by 2027. So far in 2024 and 2025 just under 50,000 people have benefited from actions that expand opportunities, strengthen communities and contribute to quality of life.

Our People: highlight

We support and subscribe to the Mind in Focus Program of the UN Global Compact in Brazil – dedicated to promoting employee mental health and well-being: reinforcing our commitment to a healthy and inclusive work environment.

Solid governance: highlight

Maintaining its long-upheld high standards of ethics and transparency, Cemig complies with the targets set by the UN Global Compact Transparency Movement: 30,000 professionals of Cemig supplier companies have been trained in the Cemig Code of Conduct, disseminating the culture of responsible practices throughout the Company’s supply and service chain. Underlining its commitment to data protection and integrity of the value chain, Cemig has also maintained a zero rate of cybersecurity incidents.

Sustainalytics: an overall highlight

Sustainalytics reports Cemig rising significantly in its Sustainability Ratings, rating its ESG Risk Score now at 20.4 – this positions Cemig in the medium risk category, with high performance in ESG management. This score is an improvement of 1.9 points from the prior assessment, indicating progress superior to the majority of its peers in levels of management of environmental, social and governance risks.

Sustainalytics’ ESG Rating is one of the leading global references for investors and stakeholders to assess companies’ performance in sustainability. Cemig’s increasing scores in this rating underline its commitment to responsible practices, and further its attractiveness for investors who prioritize ESG criteria.

It also positions Cemig as a power sector leader in sustainability, especially among companies with similar market cap.

Cemig: presence in the leading sustainability indices

Indicators

We have reorganized our records of sustainability indicators to align with our new Cemig Materiality Matrix (pages 6–7 of the Cemig Sustainability Report). This matrix classifies eight themes as material: three are considered in two categories, four are classified as having financial materiality, and one is categorized as material for impact. This reorganization aims to strengthen the coherence between the reported indicators and the themes that are priority for Cemig and its stakeholders.

* For Cemig GT only. The figure for Cemig D has not yet been calculated.

Cemig’s shares and ADRs

By aggregate volume of its common (ON) and preferred (PN) shares traded, Cemig was the fourth most liquid company in Brazil’s electricity sector, and among the most traded in the Brazilian equity market.

On the NYSE, volume traded in ADRs for Cemig’s preferred shares (CIG) in 9M25 was US$ 993.78 million: we see this as reflecting recognition by the investor market, reaffirming Cemig as a global investment option.

The benchmark Ibovespa index of the São Paulo Stock Exchange rose 21.58% in 9M25, while Cemig’s PN (preferred) shares rose 12.99% and its common shares (ON) rose 7.76%. In New York the ADRs for Cemig’s preferred shares rose 28.27% in the period, and the ADRs for its common shares rose 17.64%.

Cemig’s generation plants

For the plants of Cemig Sim, the installed capacity is given in MWac, and physical guarantee has been estimated in the table as being equal to the estimated generation.

See more details of Cemig Sim's expansion projects on the next page.

RAP: July 2025 – June 2026 cycle

The values of RAP for the 2025–26 cycle came into force in July 2025, incorporating the effects for Cemig of the remeasurement of the national grid (‘RBSE’) financial component, as defined by Aneel.

* The figures for indemnity/reimbursement of National Grid components are included in the RAP of Cemig (first table).

Cemig currently has state environmental (REA) approval for large-scale Strengthening and Enhancement works, with total capex of R$ 1,088.7 million, and for investments of R$ 231.3 million related to Lot 1 of Auction 02/2022 (with completion of works planned for 2028).

Transmission: Regulatory Revenue and Ebitda

Complementary information

Cemig D

1. Refers to the quantity of electricity for calculation of the regulatory charges charged to free consumer clients ("Portion A")

2. Sum of the demand on which the TUSD is invoiced, according to demand contracted ("Portion B").

Cemig GT

Cemig, Consolidated

Disclaimer

Certain statements and estimates in this material may represent expectations about future events or results which are subject to risks and uncertainties that may be known or unknown. There is no guarantee that events or results will occur as referred to in these expectations.

These expectations are based on present assumptions and analyses from the point of view of our management, in accordance with their experience and other factors such as the macroeconomic environment, market conditions in the electricity sector, and expected future results, many of which are not under our control.

Important factors that could lead to significant differences between actual results and the projections about future events or results include: Cemig’s business strategy, Brazilian and international economic conditions, technology, our financial strategy, changes in the electricity sector, hydrological conditions, conditions in the financial and energy markets, uncertainty on our results from future operations, plans and objectives; and other factors. Due to these and other factors, our results may differ significantly from those indicated in or implied by such statements.

The information and opinions herein should not be understood as a recommendation to potential investors, and no investment decision should be based on the veracity, currentness or completeness of this information or these opinions. None of our staff nor any party related to any of them or their representatives shall have any responsibility for any losses that may arise as a result of use of the content of this material.

To evaluate the risks and uncertainties as they relate to Cemig, and to obtain additional information about factors that could give rise to different results from those estimated by Cemig, please consult the section on Risk Factors included in the Reference Form filed with the Brazilian Securities Commission (CVM), and in the 20-F Form filed with the US Securities and Exchange Commission (SEC).

Financial amounts are in R$ million (R$ mn) unless otherwise stated.

Financial data reflect the adoption of IFRS.

COMPANHIA ENERGÉTICA DE MINAS GERAIS - CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

CEMIG GERAÇÃO E TRANSMISSÃO S.A.

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 06.981.176/0001-58
COMPANY REGISTRY (NIRE): 31300020550

NOTICE TO THE MARKET
Liquidation of the 11th Issue Debentures of Cemig GT

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“Cemig”), a category “A” publicly-held company with shares traded on the stock exchanges of São Paulo and New York, hereby informs its shareholders and the market in general that, on November 18, 2025, CEMIG GERAÇÃO E TRANSMISSÃO S.A. (“Cemig GT”), a publicly-held company and wholly owned subsidiary of Cemig, concluded the financial liquidation of the 11th (eleventh) issue of simple, unsecured debentures, not convertible into shares, with an additional personal guarantee, in two series (“Issue”), for public distribution under the automatic registration procedure with the Brazilian Securities and Exchange Commission (“CVM”), which are guaranteed by Cemig (“Debentures”).

A total of 1,500,000 (one million five hundred thousand) Debentures were issued, totaling R$1,500,000,000.00 (one billion five hundred million reais), subscribed as follows:

The proceeds obtained by Cemig GT from the Issue of Debentures will be allocated exclusively to the reimbursement of expenses, expenditures and/or debts related to the implementation of a project classified as priority, pursuant to Law 12,431, of June 24, 2011, as amended.

Finally, we hereby inform that the credit rating agency Moody’s attributed an ‘AAA.br’ rating to the Issue.

This notice is for information purposes only, under the terms of the legislation in force, and should not be interpreted as a selling material, or an offer, invitation, or request for the acquisition of the Debentures.

Belo Horizonte, November 18, 2025.

Andrea Marques de Almeida

Vice President of Finance and Investor Relations

COMPANHIA ENERGÉTICA DE MINAS GERAIS - CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

MATERIAL FACT

Collective Bargaining Agreement Regarding Health Plans

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“CEMIG” or “Company”), a publicly-held company with shares traded on the stock exchanges of São Paulo and New York, under CVM Resolution 44/2021, hereby informs its shareholders and the market in general, further to the Material Facts disclosed on September 19, 2025, September 12, 2025, and February 20, 2025, that an agreement entered into with employee representative entities was approved on this date by the Regional Labor Court of the 3rd Region, in connection with the collective bargaining agreement no. 0011731-13.2025.5.03.0000. The agreement was signed with the Intermunicipal Union of Workers in the Energy Industry of Minas Gerais (SINDIELETRO); the Union of Engineers of the State of Minas Gerais (SENGE); the Union of Industrial Technicians of Minas Gerais (SINTEC); the Union of Utility Workers of Juiz de Fora, and the retired employees of the Association of Retired Employees and Pensioners of Cemig and its Subsidiaries (AEA).

This agreement, together with the previous one already approved with other labor unions, as disclosed in the Material Fact of September 19, 2025, establishes a buyout payment for compensatory indemnity in a maximum total amount of R$1,250,000,000.00 (one billion, two hundred and fifty million reais), to be paid on a pro rata basis in 6 (six) installments, with the final installment due in 2030. This amount considers a total of 15,496 (fifteen thousand, four hundred and ninety-six) retired employees and pensioners, all of whom were active and enrolled in the CEMIG Saúde PSI health plan in February 2025.

Together, the two agreements enable the transition of the 15,496 (fifteen thousand, four hundred and ninety-six) participants to new health plans, with the termination of Cemig’s sponsorship of the PSI health plan as of December 31, 2025.

The agreement has a resolutive nature and applies to those represented by or affiliated with the signatory entities.

CEMIG reaffirms its commitment to keeping shareholders and the market in general informed about this matter, under CVM regulations and applicable legislation.

Belo Horizonte, December 03, 2025.

Andrea Marques de Almeida

Vice President of Finance and Investor Relations

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

CEMIG GERAÇÃO E TRANSMISSÃO S.A.

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 06.981.176/0001-58

COMPANY REGISTRY (NIRE): 31300020550

Notice to the Market

Injunction granted in Public Civil Action against Auction of four small power plants

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“CEMIG”), a publicly-held company with shares traded on the stock exchanges of São Paulo and New York, and CEMIG GERAÇÃO E TRANSMISSÃO S.A. (“CEMIG GT”), a publicly-held company and the wholly-owned subsidiary of CEMIG, hereby inform its shareholders and the market in general, further to the Notices to the Market disclosed on May 23, 2025, May 20, 2025, March 24, 2025, February 21, 2025, and January 10, 2025, that the Court of the 1st Public Treasury and Government Agencies Court of the District of Belo Horizonte has granted an injunction in a public civil action filed by the Federação dos Trabalhadores nas Indústrias Urbanas no Estado de Minas Gerais to suspend the processing of the divestment procedure arising from the public Auction for the sale of the rights to operate four small-scale power generation plants.

The decision covers the agreement resulting from the Auction held on December 05, 2024, for the divestment of the Machado Mineiro, Sinceridade, Martins, and Marmelos power plants, which are not part of the Company’s Strategic Plan. CEMIG will file an appeal and pursue all legal remedies at the appropriate judicial levels.

CEMIG and CEMIG GT reaffirm their commitment to keeping shareholders, the market in general, and other stakeholders duly and timely informed of any developments on this matter, under CVM regulations and legislation in force.

Belo Horizonte, December 05, 2025.

Andrea Marques de Almeida

Vice President of Finance and Investor Relations

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

CEMIG GERAÇÃO E TRANSMISSÃO S.A.

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 06.981.176/0001-58

COMPANY REGISTRY (NIRE): 31300020550

Notice to the Market

Suspension of injunction in Public Civil Action against Auction of four small power plants

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“CEMIG”), a publicly-held company with shares traded on the stock exchanges of São Paulo and New York, and CEMIG GERAÇÃO E TRANSMISSÃO S.A. (“CEMIG GT”), a publicly-held company and the wholly-owned subsidiary of CEMIG, hereby inform its shareholders and the market in general, further to the Notices to the Market disclosed on December 05, 2025, May 23, 2025, May 20, 2025, March 24, 2025, February 21, 2025, and January 10, 2025, that the Court of Justice of the State of Minas Gerais has suspended, until the final judgment on the merits, the injunction granted in the records of Public Civil Action No. 1002307-24.2025.8.13.0024 against the public Auction for the sale of the rights to operate four small-scale power generation plants.

Thus, the decision restores the effects of the agreement resulting from the Auction held on December 05, 2024, for the divestment of the Machado Mineiro, Sinceridade, Martins, and Marmelos power plants, which are not part of the Company’s Strategic Plan, enabling the continuation of the divestment process.

CEMIG and CEMIG GT reaffirm their commitment to keeping shareholders, the market in general, and other stakeholders duly and timely informed of any developments on this matter, under CVM regulations and legislation in force.

Belo Horizonte, December 08, 2025.

Andrea Marques de Almeida

Vice President of Finance and Investor Relations

COMPANHIA ENERGÉTICA DE MINAS GERAIS - CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

MATERIAL FACT

CEMIG announces R$44 billion investment plan for 2026-2030

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“CEMIG” or “Company”), a publicly-held company with shares traded on the stock exchanges of São Paulo and New York, under CVM Resolution 44/2021, hereby informs its shareholders and the market in general that its Board of Directors, at a meeting held on December 11, 2025, approved the update of the Company’s Strategic Plan and Multi-Year Plan for the 2026-2030 Cycle, with an estimated investment plan of R$44 billion.

The “Focus on Minas and Win” Strategic Plan, implemented since 2019, has promoted a profound operational and strategic transformation at the Company, driving significant efficiency gains, portfolio realignment through divestments of non-core assets, and the prioritization of investments in Minas Gerais.

The corporate strategy is structured around pillars that guide its long-term priorities: health and safety, efficiency and operational efficiency aligned with the evolution of the customer experience, modernization and resilience of power grids, expansion in centralized generation and distributed generation, modernization of power plants, preparation for the full opening of the energy market, and leadership in the energy transition, supported by digitalization, innovation, and new technologies.

The planned investments are expected to capture structural opportunities in the sector, ensure greater reliability of the power system, and accelerate the energy transition, sustaining long-term value creation for shareholders and society, through a results-oriented management approach grounded in sustainability.

For 2026, the plan provides for investments of approximately R$6.7 billion, allocated as follows:

¹ Includes investments in IT and Innovation The investments presented reflect estimates based on the Company’s strategic plans for its businesses.

The first year is already included in the approved budget. The remaining years may be subject to changes due to various factors and market conditions, and the final amounts will depend on approval by the Board of Directors.

Belo Horizonte, December 12, 2025.

Andrea Marques de Almeida

Vice President of Finance and Investor Relations

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

MATERIAL FACT

Single agreement in collective bargaining agreements on health plan

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“CEMIG” or “Company”), a publicly-held company with shares traded on the stock exchanges of São Paulo and New York, under CVM Resolution 44/2021, hereby informs its shareholders and the market in general, further to the Material Facts disclosed on December 03, 2025, September 19, 2025, September 12, 2025, and February 20, 2025, that, on this date, the Regional Labor Court of the 3rd Region (TRT-3) approved a single agreement entered into with the employee representative entities, within the scope of collective bargaining agreements 0011802-15.2025.5.03.0000 and 0011731-13.2025.5.03.0000, involving the Union of Electric Power Workers of Southern Minas Gerais (SINDSUL), the Federation of Workers in Urban Industries of Minas Gerais (FTIUMG), the Intermunicipal Union of Workers in the Energy Industry of Minas Gerais (SINDIELETRO); the Union of Engineers of the State of Minas Gerais (SENGE); the Union of Industrial Technicians of Minas Gerais (SINTEC); the Union of Utility Workers of Juiz de Fora, and the retired employees of the Association of Retired Employees and Pensioners of Cemig and its Subsidiaries (AEA).

The new agreement unifies and replaces the previous agreements already approved between Cemig and the labor unions, as disclosed in the Material Facts of December 03, 2025 and September 19, 2025, limiting the payment of a compensatory indemnification (buyout) to a maximum aggregate amount of R$1,280,000,000.00 (one billion and two hundred and eighty million reais), to be paid on a pro rata basis in 6 (six) installments, with the final installment due in 2030. Upon execution of the agreement, Cemig shall bear no responsibility for losses, deficits, insufficiencies, financial losses, or technical or actuarial imbalances of the new health plans, whose funding shall be entirely borne by the beneficiaries. Financial budgetary, technical, and actuarial management shall be the responsibility of the governance bodies of the Cemig Saúde Operator and the Management Committee of the new plans.

The single agreement enables the transition of the 15,496 (fifteen thousand, four hundred and ninety-six) participants of the ProSaúde Integrado Plan (PSI) to the new Cemig Saúde health plans, with the termination of Cemig’s sponsorship of the PSI as of December 31, 2025. As a result, Cemig concludes its direct involvement in the management and funding of retirees’ health plans.

The agreement approved by TRT-3 will lead to the extinction of judicial claims discussing the right to health plan funding, covering active employees, retirees, and pensioners represented by or affiliated with the signatory entities.

CEMIG reaffirms its commitment to keeping shareholders and the market in general informed about this matter, under CVM regulations and applicable legislation.

Belo Horizonte, December 12, 2025.

Andrea Marques de Almeida

Vice President of Finance and Investor Relations 

COMPANHIA ENERGÉTICA DE MINAS GERAIS - CEMIG

PUBLICLY-HELD COMPANY

CORPORATE TAXPAYER’S ID (CNPJ): 17.155.730/0001-64

COMPANY REGISTRY (NIRE): 31300040127

NOTICE TO THE MARKET

Cemig SIM concludes the acquisition of 10MWp in solar power plants

COMPANHIA ENERGÉTICA DE MINAS GERAIS – CEMIG (“CEMIG”), a publicly-held company with shares traded on the stock exchanges of São Paulo and New York, hereby informs its shareholders and the market in general that its wholly-owned subsidiary CEMIG SOLUÇÕES INTELIGENTES EM ENERGIA S.A. (“Cemig SIM”) has, on this date, concluded the acquisition of a 51% equity interest in two distributed generation photovoltaic power plants (“UFVs”) and 100% of one UFV, totaling 10 MWp of installed capacity, for an amount of R$52.8 million.

As a result of this acquisition, CEMIG SIM has terminated the partnerships previously in place and now holds full ownership interests in all proprietary assets in its portfolio, in line with CEMIG’s Strategic Planning.

CEMIG reaffirms its commitment to keep shareholders, the market in general, and other stakeholders duly and timely informed, in accordance with CVM regulations and applicable legislation.

Belo Horizonte, December 19, 2025.

Andrea Marques de Almeida

Vice President of Finance and Investor Relations