SEC Form 6-K filed by KT Corporation

2Q24 Earnings Release

Disclaimer This presentation has been prepared by KT Corp.(the “Company”) in accordance with K-IFRS. This presentation contains forward-looking statements, which are subject to risks, uncertainties, and assumptions. This presentation is being presented solely for your information and is subject to change without notice. No presentation or warranty, expressed or implied, is made and no reliance should be placed on the accuracy, actuality, fairness, or completeness of the information presented. If you have any questions related to this material, please contact the IR department. Tel: +82-70-4193-4036 (IR Department) 2

Contents 1 2Q24 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix

1 2Q24 Highlights Financials (Unit: KRW bn) Cons. Sep. Revenue Revenue 6,546.4bn (YoY +0.0%) 4,548.3bn (YoY +1.4%) Operating Operating * * 494.0bn (YoY -14.3% ) 358.8bn (YoY -12.0% ) Profit Profit *OP(Separate) 423.3bn (YoY +3.9%), OP(Consolidated) 558.4bn (YoY -3.1%) excluding impact of wage negotiation results 『 Pursuing structural change to enhance profitability and transforming into an AICT Company to strengthen growth potential』 • [B2C] Stable revenue growth in Wireless, Broadband and IPTV businesses • [B2B] Restructuring low-profit businesses to increase profitability • [Subsidiaries] Continued high growth, led mainly by real estate, IDC and Cloud Shareholder Return Management Strategy Enhancement of Shareholder Value AICT Company ✓ (July) 2Q quarterly dividend paid (DPS: 500KRW)✓ (June) KT-Microsoft strategic partnership established ✓ (May) treasury shares canceled (2% of outstanding shares) for a full-scale collaboration in AI, Cloud, and IT 4

Contents 1 2Q24 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix

K-IFRS / Consolidated 1 Income Statement • Steady service revenue led by growth of core businesses, offsetting the impact of portfolio restructuring • OP -14.3% YoY with increased labor costs due to early settlement of annual wage negotiation (Unit: KRW bn) 2Q23 1Q24 2Q24 QoQ YoY Operating Revenue 6,547.5 6,654.6 6,546.4 -1.6% 0.0% Service Revenue 5,834.4 5,722.7 5,776.6 0.9% -1.0% Sale of goods 713.1 931.9 769.8 -17.4% 7.9% 5,971.4 6,148.1 6,052.4 -1.6% 1.4% Operating Expense Operating Income 576.1 506.5 494.0 -2.4% -14.3% Margin 8.8% 7.6% 7.5% -0.1%p -1.3%p 1 Margin 9.9% 8.9% 8.6% -0.3%p -1.3%p -28.0 22.5 62.7 178.9% - Non-op. Income/Loss Income before taxes 548.1 529.0 556.7 5.2% 1.6% Net Income 432.5 393.0 410.5 4.5% -5.1% Margin 6.6% 5.9% 6.3% +0.4%p -0.3%p EBITDA 1,505.3 1,480.2 1,460.2 -1.4% -3.0% 23.0% 22.2% 22.3% +0.1%p -0.7%p Margin 1 1) OP Margin = Operating Income/Service Revenue 6

K-IFRS / Consolidated 2 Operating Expenses • Op. expenses +1.4% YoY, with increase in labor cost and general expense, despite decrease in selling expense (Unit: KRW bn) 2Q23 1Q24 2Q24 QoQ YoY Operating Expenses 5,971.4 6,148.1 6,052.4 -1.6% 1.4% 1,131.5 1,100.9 1,213.2 10.2% 7.2% Labor Cost General Expense 2,690.6 2,674.2 2,708.3 1.3% 0.7% - Depreciation 929.2 973.7 966.2 -0.8% 4.0% 662.8 726.5 656.6 -9.6% -0.9% Cost of Service Selling Expense 633.9 599.6 600.8 0.2% -5.2% Cost of Goods sold 852.6 1,046.9 873.5 -16.6% 2.5% [Selling Expense (KT Separate)] (Unit: KRW bn) ]] 2Q23 1Q24 2Q24 QoQ YoY 637.0 620.6 618.6 -0.3% -2.9% Selling Expense 7

K-IFRS / Consolidated 3 Balance Sheet • Net debt/equity ratio decreased by YoY 11.1%p. (Unit: KRW bn) Jun 30, 2023 Mar 31, 2024 Jun 30, 2024 QoQ YoY 39,756.0 42,710.0 43,144.4 1.0% 8.5% Assets 1,805.5 3,000.7 3,786.7 26.2% 109.7% Cash & Cash equivalents 21,302.3 24,127.8 24,162.5 0.1% 13.4% Liabilities 10,036.0 10,151.4 10,150.6 0.0% 1.1% Borrowings 18,453.7 18,582.2 18,981.9 2.2% 2.9% Equity 1,564.5 1,564.5 1,564.5 0.0% 0.0% Capital Stock 8,230.5 7,150.7 6,363.9 -11.0% -22.7% Net Debt Debt / Equity 115.4% 129.8% 127.3% -2.5%p 11.9%p Net Debt / Equity 44.6% 38.5% 33.5% -5.0%p -11.1%p 134.9% 131.1% 130.1% 129.8% 127.0% 127.3% 124.3% 124.8% 122.6% 122.5% 121.5% 118.7% 117.9% 115.4% D 부채비율 ebt/Equity 46.6% 44.6% 순부채비율 42.9% Net Debt/Equity 40.6% 41.0% 39.5% 37.4% 38.5% 38.5% 33.5% 32.4% 33.0% 32.7% 29.7% 1Q21 2Q21 3Q21 4Q21 1Q22 2Q22 3Q22 4Q22 1Q23 2Q23 3Q23 4Q23 1Q24 2Q24 8

K-IFRS / Separate and major subsidiaries 4 CAPEX • ’24.1H CAPEX Execution: KRW 960.9bn (KT Separate), KRW 374.1 bn (Major Subsidiaries) (Unit: KRW bn) 3,533 3,452 3,319 692 782 907 ■ Major Subsidiaries’ CAPEX Includes Finance, Media, Cloud/IDC, 1,335 2,760 2,721 Real Estate and etc. 2,412 374 ■ KT Separate CAPEX 961 Access network, Backbone Network, 2021 2022 2023 1H24 B2B and etc. KT 주요 Major그룹사 Subsidiaries 9

Contents 1 2Q24 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix

K-IFRS / Separate 1 KT - Wireless • Wireless service revenue +2.7% YoY, with 5G subscribers exceeding 10M(penetration rate 75%) • Enhanced customer service with 5G online-only plans, OTT subscription services, etc. (Unit: KRW bn) 2Q23 1Q24 2Q24 QoQ YoY Wireless 1,722.2 1,736.5 1,765.1 1.6% 2.5% Wireless Service 1,634.4 1,649.8 1,677.9 1.7% 2.7% Interconnection 87.8 86.7 87.2 0.6% -0.7% Wireless Subscribers (Unit: Thousands) 24,621 24,903 24,897 24,834 24,904 9,408 9,117 9,722 9,948 10,093 Handset(5G) 4,183 4,528 3,795 3,519 3,364 (exc. 5G) Handset(5G외) 2nd device & IoT 4,144 4,242 4,276 4,313 3,998 MVNO 7,168 7,138 7,134 6,978 7,091 2Q23 3Q23 4Q23 1Q24 2Q24 11

K-IFRS / Separate 2 KT - Fixed Line • Broadband revenue +1.0% YoY, due to the increase of GiGA subscribers and value-added services • Media revenue +0.9% YoY, led by increasing premium subscribers (Unit: KRW bn) 2Q23 1Q24 2Q24 QoQ YoY Fixed Line 1,320.7 1,322.4 1,316.6 -0.4% -0.3% Broadband 612.4 620.8 618.5 -0.4% 1.0% Media 518.0 518.6 522.6 0.8% 0.9% Home Telephony 190.4 183.0 175.6 -4.1% -7.8% Broadband Subscribers IPTV Subscribers (Unit: Thousands) (Unit: Thousands) % Subscribers 가입자수 GiGA 비중(%) 9,899 9,862 9,827 9,812 9,810 9,470 9,430 9,423 9,418 9,409 68.7% 68.5% 68.3% 68.0% 67.6% 2Q23 3Q23 4Q23 1Q24 2Q24 2Q23 3Q23 4Q23 1Q24 2Q24 12

K-IFRS / Separate 3 KT - B2B Services • B2B Service rev. -1.0% YoY, due to restructuring of low-profit businesses • Pursuing a sustainable portfolio by focusing on profitability and growth of promising businesses (Unit: KRW bn) 2Q23 1Q24 2Q24 QoQ YoY B2B Service 891.2 895.0 882.7 -1.4% -1.0% Real Estate, etc. 84.5 86.7 83.6 -3.6% -1.1% Corp. Broadband/Data Revenue Revenue of 5 Major Growth Drivers (Unit: KRW bn) (Unit: KRW bn) 321.6 323.5 327.0 316.9 318.1 YoY +3.2% QoQ +1.1% 96.0 93.9 92.8 YoY +10.3% 87.1 73.7 QoQ +3.5% 2Q23 3Q23 4Q23 1Q24 2Q24 2Q23 3Q23 4Q23 1Q24 2Q24 ※ Corp. Broadband/data rev includes: ※ 5 Major Growth Drivers include: Leased line, Kornet, VPN, Global data AICC, IoT, Smart Mobility, Smart Space, Energy Biz. 13

K-IFRS / Consolidated(each subsidiary) 4 Major Subsidiaries • kt cloud revenue +17.1% YoY, with increased demand for data centers and expansion of DBO* business *DBO(Design-Build-Operate): a project where a single contractor is appointed to design, build and operate a data center for a certain period • kt estate revenue +7.1% YoY, led by balanced growth from hotel, office, and housing rentals (Unit: KRW bn) Revenue of Major Subsidiaries (consolidated) 2Q23 1Q24 2Q24 QoQ YoY BC Card 1,049.2 935.6 977.7 4.5% -6.8% Skylife 261.3 254.4 254.6 0.1% -2.5% Content Subsidiaries1 158.8 138.6 135.4 -2.3% -14.8% kt cloud 153.8 175.2 180.1 2.8% 17.1% KT Estate 145.4 135.7 155.8 14.8% 7.1% 1) Nasmedia(PlayD incl.), KT Studiogenie(Genie music, Storywiz, and others incl.) (Unit: KRW bn) Subsidiaries’ OP Contribution 168.6 135.1 128.4 112.7 69.3 2Q23 3Q23 4Q23 1Q24 2Q24 14

Contents 1 2Q24 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix

1 K-IFRS Income Statement (Unit: KRW bn) Consolidated 2Q23 3Q23 4Q23 1Q24 2Q24 KT Separate 2Q23 3Q23 4Q23 1Q24 2Q24 Operating revenue 6,547.5 6,697.4 6,687.6 6,654.6 6,546.4 Operating revenue 4,487.4 4,673.0 4,592.0 4,694.8 4,548.3 Service revenue 5,834.4 5,842.5 5,720.2 5,722.7 5,776.6 Service revenue 4,018.6 4,020.0 3,941.2 4,040.6 4,048.0 713.1 855.0 967.4 931.9 769.8 468.8 653.0 650.8 654.2 500.3 Sale of goods Handset revenue Operating expense 5,971.4 6,375.5 6,422.0 6,148.1 6,052.4 Operating expense 4,079.9 4,479.5 4,395.7 4,301.0 4,189.5 Cost of Service 5,118.8 5,331.5 5,372.9 5,101.2 5,178.9 Cost of Service 3,618.7 3,808.8 3,707.7 3,624.7 3,696.8 Labor cost 1,131.5 1,191.0 1,157.8 1,100.9 1,213.2 Labor cost 583.2 634.6 530.5 540.7 631.3 2,690.6 2,732.8 2,843.7 2,674.2 2,708.3 1,745.5 1,828.6 1,925.0 1,777.1 1,804.2 General expense General expense Cost of service 662.8 784.5 725.5 726.5 656.6 Cost of service 638.7 695.2 594.2 673.2 630.6 Selling expense 633.9 623.2 645.9 599.6 600.8 Selling expense 651.3 650.4 657.9 633.7 630.7 Cost of Goods sold 852.6 1,044.0 1,049.1 1,046.9 873.5 Cost of Devices sold 461.2 670.6 688.1 676.3 492.6 Operating income 576.1 321.9 265.6 506.5 494.0 Operating income 407.5 193.5 196.3 393.8 358.8 N-OP income (loss) -28.0 28.4 -277.6 22.5 62.7 N-OP income (loss) -12.8 34.7 -91.6 72.4 50.3 N-OP income 185.5 255.0 105.8 323.1 325.8 N-OP income 161.2 226.7 50.0 309.0 260.0 N-OP expense 219.5 223.7 340.7 310.9 260.1 N-OP expense 174.0 192.0 141.6 236.6 209.7 Equity Method (G/L) 6.0 -2.8 -42.7 10.2 -3.0 Income bf tax 548.1 350.3 -12.0 529.0 556.7 Income bf tax 394.6 228.2 104.8 466.1 409.2 Income tax 115.6 62.0 29.7 136.0 146.2 Income tax 89.6 17.6 7.0 112.1 94.7 432.5 288.3 -41.7 393.0 410.5 305.0 210.6 97.8 354.0 314.5 Net income Net income NI contribution to KT 394.5 264.3 54.4 375.5 393.1 EBITDA 1,505.3 1,259.9 1,279.2 1,480.2 1,460.2 1,190.0 979.9 1,031.5 1,199.1 1,162.9 EBITDA EBITDA Margin 23.0% 18.8% 19.1% 22.2% 22.3% 26.5% 21.0% 22.5% 25.5% 25.6% EBITDA Margin 16

2 K-IFRS Balance Sheet (Unit: KRW bn) Consolidated 2Q23 3Q23 4Q23 1Q24 2Q24 KT Separate 2Q23 3Q23 4Q23 1Q24 2Q24 Assets 39,756.0 43,974.8 42,710.0 42,710.0 43,144.4 Assets 29,592.2 30,814.8 30,308.9 30,334.8 30,464.8 Current assets 11,405.7 15,520.6 14,518.2 14,997.4 15,175.2 Current assets 6,172.5 7,505.4 7,088.6 7,578.4 7,451.7 Cash & cash equivalents 1,805.5 3,110.4 2,879.6 3,000.7 3,786.7 Cash & cash equi. 625.7 1,477.3 1,242.0 1,331.6 1,722.5 Trade & other receivables 3,933.1 4,515.4 4,287.3 4,571.4 4,161.7 Trade & other rec. 3,018.4 3,425.8 3,190.3 3,546.3 3,097.6 Inventories 636.9 707.4 912.3 899.1 964.0 Inventories 260.1 276.6 368.1 310.3 404.1 Other current asset 5,030.1 7,187.3 6,438.9 6,526.2 6,262.7 Other current asset 2,268.4 2,325.6 2,288.2 2,390.2 2,227.5 1,269.5 1,270.3 1,252.1 1,249.2 1,233.6 1,351.6 1,360.3 1,340.2 1,335.4 1,312.5 - Prepaid_Contract cost - Prepaid_Contract cost 565.8 590.7 581.8 620.4 611.1 500.3 527.0 535.8 540.2 548.6 - Contract assets - Contract assets Non-current assets 28,350.3 28,454.1 28,191.8 27,712.6 27,969.2 Non-current assets 23,419.6 23,309.4 23,220.4 22,756.4 23,013.1 Trade & other rec 490.7 406.0 451.7 381.2 398.4 Trade & other rec 402.8 322.1 370.7 298.8 321.1 Tangible assets 14,675.6 14,669.9 14,872.1 14,585.7 14,591.7 Tangible assets 11,276.3 11,288.5 11,492.8 11,214.3 11,264.4 Other current assets 13,184.0 13,378.2 12,868.1 12,745.7 12,979.1 Other current assets 10,775.2 10,753.0 10,380.2 10,281.4 10,472.9 - Prepaid_Contract cost 480.4 486.0 475.4 465.1 471.4 - Prepaid_Contract cost 469.8 478.7 464.2 451.9 453.8 - Contract assets 236.8 248.7 240.1 229.3 226.3 - Contract assets 196.3 227.5 219.1 207.4 204.1 Liabilities 21,302.3 25,253.1 24,148.9 24,127.8 24,162.5 Liabilities 14,817.5 15,831.4 15,265.4 15,335.6 15,166.7 Current liabilities 9,862.9 13,478.5 13,147.5 14,046.1 14,095.2 Current liabilities 6,153.7 6,925.2 6,957.5 7,477.8 7,315.1 Trade & other payables 6,225.9 9,264.6 8,054.9 8,282.4 8,052.3 Trade & other payables 4,253.7 5,021.2 4,459.0 4,864.3 4,694.7 Short-term borrowings 2,105.6 2,368.7 3,058.6 3,538.6 3,595.0 Short-term borrowings 1,131.5 1,173.8 1,725.2 1,914.9 1,789.5 Others 1,531.4 1,845.2 2,033.9 2,225.1 2,447.9 Others 768.6 730.2 773.3 698.5 830.8 - Contract liabilities 264.1 245.2 229.2 239.3 231.2 - Contract liabilities 235.1 222.6 223.9 227.0 206.9 Non-current liabilities 11,439.4 11,774.6 11,001.4 1,0081.7 10,067.3 Non-current liabilities 8,663.8 8,906.2 8,307.9 7,857.9 7,851.6 Trade & other payables 818.5 856.0 819.6 554.1 556.2 Trade & other payables 1,331.9 1,337.9 1,364.8 1,074.2 1,063.8 Long-term borrowings 7,930.4 7,940.8 7,159.6 6,612.8 6,555.6 Long-term borrowings 6,205.6 6,497.5 5,834.7 5,652.2 5,675.7 2,690.5 2,977.9 3,022.3 2,914.8 2,955.4 1,126.3 1,070.8 1,108.4 1,131.5 1,112.0 Others Others 39.3 37.2 49.6 48.7 43.6 33.8 32.4 35.8 36.0 26.4 - Contract liabilities - Contract liabilities Equity 18,453.7 18,721.7 18,561.1 18,582.2 18,981.9 Equity 14,774.7 14,983.4 15,043.5 14,999.2 15,298.1 14,404.0 14,570.7 14,494.4 14,361.5 14,452.7 12,429.0 12,541.3 12,544.4 12,390.5 12,404.2 Retained earnings Retained earnings 17

K-IFRS / Separate 3 Subscribers (Unit: Thousands) Wireless Subscribers 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 QoQ YoY Total 24,621 24,903 24,897 24,834 24,904 0.3% 1.1% - MNO 17,643 17,735 17,759 17,743 17,770 0.2% 0.7% - MVNO 6,978 7,168 7,138 7,091 7,134 0.6% 2.2% 1) 5G Handset 9,117 9,408 9,722 9,948 10,093 1.5% 10.7% 2) Churn rate 1.0% 1.1% 1.1% 1.1% 1.0% -0.1%p 0.0%p 3) ARPU (KRW) 33,948 33,838 34,302 34,461 34,507 0.1% 1.6% nd 1) 5G Handset : Retroactively applied from 1Q23 based on the change of subscriber disclosure criteria by the MSIT (excludes 5G 2 Device and 5G IoT) 2) Churn rate : Based on MNO subscribers (excludes IoT) 3) ARPU = Wireless revenue* / Wireless subscribers** * Wireless revenue(3G, LTE, 5G incl.): Revenue of Voice/Data usage (Interconnection/Subscription fee exc.), VAS, Contract/ Bundled Discounts, and etc. incl. ** Wireless subscribers: Based on MSIT’s guidelines for average billed subscribers in quarter (IoT/M2M exc.) (Unit: Thousands) Fixed Line Subscribers 2Q 23 3Q 23 4Q 23 1Q 24 2Q 24 QoQ YoY Telephony 12,310 12,184 12,035 11,903 11,748 -1.3% -4.6% - PSTN 9,089 8,960 8,820 8,673 8,526 -1.7% -6.2% - VoIP 3,221 3,225 3,215 3,230 3,222 -0.2% 0.1% Broadband 9,812 9,810 9,827 9,862 9,899 0.4% 0.9% IPTV (GTV+GTS) 9,470 9,430 9,409 9,418 9,423 0.1% -0.5% ※ Number of IPTV subscribers above differs from MSIT figures that follow the IPTV law - Number of KT pay TV subscribers in 2H 2023 is 8,827,392 (6-month average) 18