[6-K] SOUTHEAST AIRPORT GROUP Current Report (Foreign Issuer)

Rhea-AI Filing Summary

Grupo Aeroportuario del Sureste (ASUR) reported mixed 4Q25 results. Total revenue rose 21.6% to Ps.10,969,074k, driven by increases across Mexico, San Juan, and Colombia. Commercial revenue per passenger also improved modestly in all regions.

Profitability weakened as EBITDA fell 4.8% to Ps.4,867,127k, while net income dropped 21.9% to Ps.2,804,945k. Majority net income declined similarly, leading earnings per share in pesos down from 11.3819 to 9.0457, and earnings per ADS in U.S. dollars from $6.3229 to $5.0251.

ASUR stepped up investment, with capex up 54.0% to Ps.3,899,344k. The balance sheet shifted from a net cash position of Ps.(6,724,001)k to net debt of Ps.16,370,228k, and the net debt to LTM EBITDA ratio moved from (0.3) to 0.8. Passenger traffic was broadly stable, with Mexico up 0.1%, Colombia up 5.7%, and Puerto Rico (San Juan) down 3.1%.

Insights

Equity analyst

Revenue grew strongly in 4Q25, but profits and leverage moved the wrong way.

ASUR delivered solid top-line expansion in 4Q25, with total revenue up 21.6% to Ps.10,969,074k, supported by all three geographies. Commercial revenue per passenger increased in Mexico, San Juan, and Colombia, showing continued success in monetizing traffic beyond aeronautical fees.

However, earnings quality deteriorated. EBITDA declined 4.8% to Ps.4,867,127k, and net income fell 21.9% to Ps.2,804,945k. Majority net income and EPS dropped at the same pace, indicating margin compression despite higher revenue.

The capital structure also shifted meaningfully. Capex rose 54.0% to Ps.3,899,344k, while cash and equivalents fell from Ps.20,083,457k to Ps.11,116,335k. Net debt swung from a net cash position of Ps.(6,724,001)k to net debt of Ps.16,370,228k, and net debt/LTM EBITDA moved from (0.3) to 0.8. Future disclosures for periods after December 31, 2025 will clarify whether higher leverage and weaker margins persist.

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 UNDER

THE SECURITIES EXCHANGE ACT OF 1934

For the month of February 2026

GRUPO AEROPORTUARIO DEL SURESTE, S.A.B. de C.V.

(SOUTHEAST AIRPORT GROUP)

(Translation of Registrant’s Name Into English)

México

(Jurisdiction of incorporation or organization)

Bosque de Alisos No. 47A– 4th Floor

Bosques de las Lomas

05120 México, D.F.

(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 x Form 40-F ¨

(Indicate by check mark whether the registrant by furnishing the information contained in this form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.)

Yes ¨ No x

(If “Yes” is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82- .)

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.

Grupo Aeroportuario del Sureste, S.A.B. de C.V.
By:	/s/ ADOLFO CASTRO RIVAS
	Adolfo Castro Rivas
	Chief Executive Officer

Date: February 24, 2026

Exhibit 99.1

ASUR ANNOUNCES 4Q25 RESULTS

Passenger traffic increased by 5.7% in Colombia and 0.1% in
Mexico; and decreased by 3.1% in Puerto Rico

Mexico City, February 24, 2026 - Grupo Aeroportuario del Sureste, S.A.B. de C.V. (NYSE: ASR; BMV: ASUR) (ASUR), a leading international airport group with operations in Mexico, the United States, and Colombia, today announced its results for the three- and twelve-month periods ended December 31, 2025.

4Q25 Highlights¹

· Total passenger traffic increased 0.9% YoY ("YoY"). By country of operations, passenger traffic showed the following YoY variations:

o Mexico: increased 0.1%, as a 0.7% increase in international traffic offset a 0.5% decrease in domestic traffic.

o Puerto Rico (Aerostar): decreased 3.1%, as a 4.2% decrease in domestic traffic more than offset a 5.0% increase in international traffic.

o Colombia (Airplan): increased 5.7%, reflecting increases of 9.6% and 4.6% in international and domestic traffic, respectively.

· Revenues increased 21.6% YoY to Ps.10,969.1 million. Excluding construction services, revenues remained flat YoY.

· Commercial revenue per passenger increased 1.1% YoY to Ps.131.7

· Consolidated EBITDA decreased 4.8% YoY to Ps.4,867.1 million.

· Adjusted EBITDA margin (excluding IFRIC 12 effect) decreased to 66.4% from 69.7% in 4Q24.

· Cash position of Ps.11,116.3 million at December 31, 2025, with Debt to LTM Adjusted EBITDA at 0.8x.

· On December 11, 2025, ASUR completed the acquisition of its ASUR US airport retail concessions at key terminals within John F. Kennedy International Airport, Los Angeles International Airport and Chicago O’Hare International Airport. From the acquisition date through December 31, 2025, these operations contributed revenues of Ps.133.1 million and EBITDA of Ps.86.1 million.

ASUR 4Q25 Page 1 of 5

Table 1: Financial and Operating Highlights1
	Fourth Quarter		% Chg.
	2024	2025
Financial Highlights
Total Revenue	9,020,577	10,969,074	21.6
Mexico	6,707,511	8,582,210	27.9
San Juan	1,384,247	1,423,049	2.8
Colombia	928,819	963,815	3.8
Commercial Revenues per PAX	130.2	131.7	1.1
Mexico	158.5	159.0	0.3
San Juan	153.9	159.4	3.6
Colombia	50.4	56.4	12.0
EBITDA	5,111,286	4,867,127	(4.8)
Net Income	3,589,717	2,804,945	(21.9)
Majority Net Income	3,414,581	2,713,713	(20.5)
Earnings per Share (in pesos)	11.3819	9.0457	(20.5)
Earnings per ADS (in US$)	6.3229	5.0251	(20.5)
Capex	2,532,698	3,899,344	54.0
Cash & Cash Equivalents	20,083,457	11,116,335	(44.6)
Net Debt	(6,724,001)	16,370,228	(343.5)
Net Debt/ LTM EBITDA	(0.3)	0.8	(338.5)
Operational Highlights
Passenger Traffic
Mexico	10,105,370	10,114,332	0.1
San Juan	3,199,545	3,100,354	(3.1)
Colombia	4,433,379	4,684,968	5.7

For a full version of ASUR’s Fourth Quarter of 2025 Earnings Release, please visit: https://www.asur.com.mx/informacion-financiera-page-0

4Q25 Earnings Call

Day: Wednesday, February 25, 2026, at 9:00 AM ET; 8:00 AM Mexico City time

Dial-in: +1 877 407 4018 (U.S. Toll-Free); +1 201 689 8471 (International)

Access Code: 13758364. Please dial-in 10 minutes before the scheduled start time.

Replay: Wednesday, February 25, 2026, at 2:00 PM ET, ending at 11:59 PM ET on Wednesday, March 4, 2026. Dial-in: +1 844 512 2921 (U.S. Toll-Free); +1 412 317 6671 (International). Access Code: 13758364

¹Unless otherwise stated, all financial figures are unaudited and prepared in accordance with International Financial Reporting Standards (IFRS). All figures in this report are expressed in Mexican pesos, unless otherwise noted. Tables state figures in thousands of Mexican pesos, unless otherwise noted. Passenger figures for Mexico and Colombia exclude transit and general aviation passengers, unless otherwise noted. Commercial revenues include revenues from non-permanent ground transportation and parking lots. U.S. dollar figures are calculated at an exchange rate of US$1.00 = Ps.18.0012 (source: Diario Oficial de la Federación de México) while Colombian peso figures are calculated at an exchange rate of COP.209.3700 = Ps.1.00 (source: Investing). Definitions for EBITDA, Adjusted EBITDA Margin, and Majority Net Income can be found on page 18 of this report.

ASUR 4Q25 Page 2 of 5

Definitions

Concession Services Agreements (IFRIC 12 interpretation). In Mexico and Puerto Rico, ASUR is required by IFRIC 12 to include in its income statement an income line, “Construction Revenues,” reflecting the revenue from construction of, or improvements to concessioned assets made during the relevant period. The same amount is recognized under the expense line “Construction Costs” because ASUR hires third parties to provide construction services. Because equal amounts of Construction Revenues and Construction Costs have been included in ASUR's income statement as a result of the application of IFRIC 12, the amount of Construction Revenues does not have an impact on EBITDA, but it does have an impact on EBITDA Margin. In Colombia, “Construction Revenues” include the recognition of the revenue to which the concessionaire is entitled for carrying out the infrastructure works in the development of the concession, while “Construction Costs” represents the actual costs incurred in the execution of such additions or improvements to the concessioned assets.

Majority Net Income reflects ASUR’s equity interests in each of its subsidiaries and therefore excludes the 40% interest in Aerostar that is owned by other shareholders. Other than Aerostar, ASUR owns (directly or indirectly) 100% of its subsidiaries.

EBITDA means net income before provision for taxes, deferred taxes, profit sharing, non-ordinary items, participation in the results of associates, comprehensive financing cost, and depreciation and amortization. EBITDA should not be considered as an alternative to net income, as an indicator of our operating performance, as an alternative to cash flow or as an indicator of liquidity. Our management believes that EBITDA provides a useful measure that is widely used by investors and analysts to evaluate our performance and compare it with other companies. EBITDA is not defined under U.S. GAAP or IFRS and may be calculated differently by different companies.

Adjusted EBITDA Margin is calculated by dividing EBITDA by total revenues excluding construction services revenues for Mexico, Puerto Rico, and Colombia and excludes the effect of IFRIC 12 with respect to the construction of, or improvements to concessioned assets. ASUR is required by IFRIC 12 to include in its income statement an income line reflecting the revenue from construction of, or improvements to concessioned assets made during the relevant period. The same amount is recognized under the expense line “Construction Costs” because ASUR hires third parties to provide construction services. In Mexico and Puerto Rico, because equal amounts of Construction Revenues and Construction Costs have been included in ASUR's income statement as a result of the application of IFRIC 12, the amount of Construction Revenues does not have an impact on EBITDA, but it does

ASUR 4Q25 Page 3 of 5

have an impact on EBITDA Margin, as the increase in revenues that relates to Construction Revenues does not result in a corresponding increase in EBITDA. In Colombia, construction revenues do have an impact on EBITDA, as construction revenues include a reasonable margin over the actual cost of construction. Like EBITDA Margin, Adjusted EBITDA Margin should not be considered as an indicator of our operating performance, as an alternative to cash flow or as an indicator of liquidity and is not defined under U.S. GAAP or IFRS and may be calculated differently by different companies.

About ASUR

Grupo Aeroportuario del Sureste, S.A.B. de C.V. (ASUR) is a leading international airport operator with a portfolio of concessions to operate, maintain, and develop 16 airports across the Americas. The Company operates nine airports in southeast of Mexico, including Cancún Airport, the largest tourist gateway in Mexico, the Caribbean, and Latin America; as well as six airports in northern Colombia, including Medellin international airport (Rionegro), the second busiest in Colombia.

ASUR also holds a 60% interest in Aerostar Airport Holdings, LLC, operator of Luis Muñoz Marin International Airport in San Juan, the capital of Puerto Rico, the island’s primary international gateway. San Juan Airport was the first and remains the only major airport in the U.S. to have successfully completed a public–private partnership under the FAA Pilot Program. ASUR has recently expanded into airport commercial services through ASUR US, which partners with airports and airlines to deliver enhanced retail and passenger experiences. ASUR Airports operates at major U.S. hubs, including Los Angeles International, Chicago O’Hare, and John F. Kennedy International, and has historically shown competitive performance against U.S. commercial revenue benchmarks.

Headquartered in Mexico, ASUR is listed on both the Mexican Bolsa (BMV) under the symbol ASUR, and on the NYSE in the U.S., where it trades under the symbol ASR. One ADS represents ten (10) B-series shares. For further information, visit www.asur.com.mx

Analyst Coverage

In accordance with Article 4.033.01 of the Mexican Stock Exchange Internal Rules, ASUR reports that the stock is covered by the following broker-dealers: Actinver, Banorte, Barclays, BBVA, BofA Merrill Lynch, Bradesco, BTG Pactual, Citi Global Markets, GBM Grupo Bursatil, Goldman Sachs, HSBC Securities, Insight Investment Research, Itau BBA Securities, Jefferies, JP Morgan, Punto Research, Santander, Scotiabank, UBS Casa de Bolsa and Vector.

ASUR 4Q25 Page 4 of 5

Please note that any opinions, estimates or forecasts with respect to the performance of ASUR issued by these analysts reflect their own views, and therefore do not represent the opinions, estimates or forecasts of ASUR or its management. Although ASUR may refer to or distribute such statements, this does not imply that ASUR agrees with or endorses any information, conclusions or recommendations included therein.

Forward Looking Statements

Some of the statements contained in this press release discuss future expectations or state other forward-looking information. Those statements are subject to risks identified in this press release and in ASUR’s filings with the SEC. Actual developments could differ significantly from those contemplated in these forward-looking statements. The forward-looking information is based on various factors and was derived using numerous assumptions. Our forward-looking statements speak only as of the date they are made and, except as may be required by applicable law, we do not have an obligation to update or revise them, whether as a result of new information, future or otherwise.

Contacts:

ASUR Adolfo Castro +52-55-5284-0408 acastro@asur.com.mx ASUR David Barlow +52-55-5284-0483 dbarlow@asur.com.mx InspIR Group Susan Borinelli +1-646-330-5907 susan@inspirgroup.com

ASUR 4Q25 Page 5 of 5

Filing Exhibits & Attachments

1 document

Press Releases

• EX-99.1 EXHIBIT 99.1 67.7 KB