KT 1Q21 Earnings ReleaseKT 1Q21 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. st The Company has applied new accounting standard of K-IFRS 1115 as of Jan 1 , 2018 and K-IFRS 1116 ‘Leases’ as of Jan st 1 , 2019. There are no obligation to apply the new standard to previous financial statements. The Company, its affiliates or representatives accept no liability whatsoever for any losses arising from any information contained in the presentation. This presentation does not constitute an offer or invitation to purchase or subscribe for any shares of the Company, and no part of this presentation shall form the Basis of or be relied upon in connection with any contract or commitment. Any decision to purchase shares of the Company could be made solely on the Basis of information, which has been publicly filed with the Securities and Exchange Commission or the Korea Stock Exchange and distributed to all investors. The contents of this presentation may not be reproduced, redistributed or passed on, directly or indirectly, to any other person or published, in whole or in part, for any purpose. If you have any related questions to this material, please contact IR department. Tel : +82-2-3495-3557, 3254, 3564, 5344 Fax : +82-2-3495-5917 2Disclaimer 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. st The Company has applied new accounting standard of K-IFRS 1115 as of Jan 1 , 2018 and K-IFRS 1116 ‘Leases’ as of Jan st 1 , 2019. There are no obligation to apply the new standard to previous financial statements. The Company, its affiliates or representatives accept no liability whatsoever for any losses arising from any information contained in the presentation. This presentation does not constitute an offer or invitation to purchase or subscribe for any shares of the Company, and no part of this presentation shall form the Basis of or be relied upon in connection with any contract or commitment. Any decision to purchase shares of the Company could be made solely on the Basis of information, which has been publicly filed with the Securities and Exchange Commission or the Korea Stock Exchange and distributed to all investors. The contents of this presentation may not be reproduced, redistributed or passed on, directly or indirectly, to any other person or published, in whole or in part, for any purpose. If you have any related questions to this material, please contact IR department. Tel : +82-2-3495-3557, 3254, 3564, 5344 Fax : +82-2-3495-5917 2

2 Financial Highlights 3 Business Overview 4 Appendix 32 Financial Highlights 3 Business Overview 4 Appendix 3

1 1Q21 Highlights Revenue and OP improved with balanced growth in Telco and Financial Digital Platform Business (unit: KRW) Service Revenue Service Revenue 6,029.4 bn. (YoY + 3.4%) 4,574.5 bn. (YoY + 3.3%) (Consolidated) (KT separate) Operating Profit Operating Profit 366.0 bn. (YoY +21.4%) 444.2 bn. (YoY +15.4%) (KT separate) (Consolidated) Digital platform businesses expansion and Group business portfolio Business Restructuring for the growth Digital platform business expansion & Group restructuring & Strategic investment Telco business competency enhancement continued for future growth √ K bank accelerated growth with √ B2B growth continued with ‘Un-tact’ capital increase (Contact-free culture) increase Dec. ‘20 Apr. ‘21 - Total deposit 5 tr. ▶ 12 tr. - AI/DX(IDC, Cloud) Rev. grew YoY +7.5% √ KT StudioGenie established - Accelerate DX Service offering(AICC, C-ITS etc.) - Share acquisition of Storywiz and √ Telco fundamental enhanced Skylife TV - Mobile ARPU YoY turnaround √ Strategic investment in ‘banksalad’ - Broadband subs net adds of 100k √ Acquisition of ‘altimedia’ (The largest net adds M/S in 1Q21) 41 1Q21 Highlights Revenue and OP improved with balanced growth in Telco and Financial Digital Platform Business (unit: KRW) Service Revenue Service Revenue 6,029.4 bn. (YoY + 3.4%) 4,574.5 bn. (YoY + 3.3%) (Consolidated) (KT separate) Operating Profit Operating Profit 366.0 bn. (YoY +21.4%) 444.2 bn. (YoY +15.4%) (KT separate) (Consolidated) Digital platform businesses expansion and Group business portfolio Business Restructuring for the growth Digital platform business expansion & Group restructuring & Strategic investment Telco business competency enhancement continued for future growth √ K bank accelerated growth with √ B2B growth continued with ‘Un-tact’ capital increase (Contact-free culture) increase Dec. ‘20 Apr. ‘21 - Total deposit 5 tr. ▶ 12 tr. - AI/DX(IDC, Cloud) Rev. grew YoY +7.5% √ KT StudioGenie established - Accelerate DX Service offering(AICC, C-ITS etc.) - Share acquisition of Storywiz and √ Telco fundamental enhanced Skylife TV - Mobile ARPU YoY turnaround √ Strategic investment in ‘banksalad’ - Broadband subs net adds of 100k √ Acquisition of ‘altimedia’ (The largest net adds M/S in 1Q21) 4

1 1Q21 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix 51 1Q21 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix 5

K-IFRS / Consolidated 1 Income Statement • Total revenue increased YoY +3.4% with balanced growth in both Telco and Digital platform business • Operating income increased YoY +15.4% with efficient cost spending (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Operating Revenue 5,831.7 6,207.3 6,029.4 -2.9% 3.4% Service Revenue 5,107.0 5,302.5 5,230.4 -1.4% 2.4% 724.7 904.7 799.1 -11.7% 10.3% Handset Revenue Operating Expense 5,446.9 6,045.5 5,585.2 -7.6% 2.5% 384.8 161.7 444.2 174.7% 15.4% Operating Income Margin 6.6% 2.6% 7.4% 4.8%p 0.8%p Margin* 7.5% 3.0% 8.5% 5.4%p 1.0%p -17.0 -178.0 24.0 Turn Black Turn Black Non-op. Income/Loss Income before taxes 367.8 -16.3 468.2 Turn Black 27.3% 227.2 37.2 326.5 777.8% 43.7% Net Income Margin 3.9% 0.6% 5.4% 4.8%p 1.5%p 1,297.2 1,067.1 1,345.3 26.1% 3.7% EBITDA Margin 22.2% 17.2% 22.3% 5.1%p 0.1%p ※ OP Margin* = Operating Income/Service Revenue 6K-IFRS / Consolidated 1 Income Statement • Total revenue increased YoY +3.4% with balanced growth in both Telco and Digital platform business • Operating income increased YoY +15.4% with efficient cost spending (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Operating Revenue 5,831.7 6,207.3 6,029.4 -2.9% 3.4% Service Revenue 5,107.0 5,302.5 5,230.4 -1.4% 2.4% 724.7 904.7 799.1 -11.7% 10.3% Handset Revenue Operating Expense 5,446.9 6,045.5 5,585.2 -7.6% 2.5% 384.8 161.7 444.2 174.7% 15.4% Operating Income Margin 6.6% 2.6% 7.4% 4.8%p 0.8%p Margin* 7.5% 3.0% 8.5% 5.4%p 1.0%p -17.0 -178.0 24.0 Turn Black Turn Black Non-op. Income/Loss Income before taxes 367.8 -16.3 468.2 Turn Black 27.3% 227.2 37.2 326.5 777.8% 43.7% Net Income Margin 3.9% 0.6% 5.4% 4.8%p 1.5%p 1,297.2 1,067.1 1,345.3 26.1% 3.7% EBITDA Margin 22.2% 17.2% 22.3% 5.1%p 0.1%p ※ OP Margin* = Operating Income/Service Revenue 6

K-IFRS / Consolidated 2 Operating Expenses (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY 5,446.9 6,045.5 5,585.2 -7.6% 2.5% Operating Expenses Labor Cost 1,003.9 1,053.8 1,024.2 -2.8% 2.0% 2,257.7 2,440.5 2,320.7 -4.9% 2.8% General Expense - Depreciation 912.4 905.4 901.2 -0.5% -1.2% 759.2 860.6 757.4 -12.0% -0.2% Cost of Service Provided Selling Expense 551.6 682.6 614.4 -10.0% 11.4% 874.4 1,008.1 868.5 -13.8% -0.7% Cost of Handset sold § Selling Expense (KT Separate) (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Selling Expense 575.8 686.3 631.0 -8.1% 9.6% 7K-IFRS / Consolidated 2 Operating Expenses (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY 5,446.9 6,045.5 5,585.2 -7.6% 2.5% Operating Expenses Labor Cost 1,003.9 1,053.8 1,024.2 -2.8% 2.0% 2,257.7 2,440.5 2,320.7 -4.9% 2.8% General Expense - Depreciation 912.4 905.4 901.2 -0.5% -1.2% 759.2 860.6 757.4 -12.0% -0.2% Cost of Service Provided Selling Expense 551.6 682.6 614.4 -10.0% 11.4% 874.4 1,008.1 868.5 -13.8% -0.7% Cost of Handset sold § Selling Expense (KT Separate) (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Selling Expense 575.8 686.3 631.0 -8.1% 9.6% 7

K-IFRS / Consolidated 3 Financial Position (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Assets 33,167.9 33,662.5 33,547.6 -0.3% 1.1% Cash & Cash equivalents 1,627.1 2,634.6 2,753.1 4.5% 69.2% Liabilities 18,099.2 18,111.1 18,209.7 0.5% 0.6% Borrowings 7,286.9 7,316.3 7,724.6 5.6% 6.0% 15,068.8 15,551.4 15,337.9 -1.4% 1.8% Equity 1,564.5 1,564.5 1,564.5 0.0% 0.0% Capital Stock 5,659.8 4,681.7 4,971.6 6.2% -12.2% Net Debt 120.1% 116.5% 118.7% 2.2%p -1.4%p Debt / Equity Net Debt / Equity 37.6% 30.1% 32.4% 2.3%p -5.2%p 132.8% 127.5% 124.9% 123.1% 121.0% 120.1% 118.7% 116.5% Debt/Equity Net Debt/Equity 37.6% 32.9% 32.8% 32.4% 31.0% 30.1% 26.7% 28.1% 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 8K-IFRS / Consolidated 3 Financial Position (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Assets 33,167.9 33,662.5 33,547.6 -0.3% 1.1% Cash & Cash equivalents 1,627.1 2,634.6 2,753.1 4.5% 69.2% Liabilities 18,099.2 18,111.1 18,209.7 0.5% 0.6% Borrowings 7,286.9 7,316.3 7,724.6 5.6% 6.0% 15,068.8 15,551.4 15,337.9 -1.4% 1.8% Equity 1,564.5 1,564.5 1,564.5 0.0% 0.0% Capital Stock 5,659.8 4,681.7 4,971.6 6.2% -12.2% Net Debt 120.1% 116.5% 118.7% 2.2%p -1.4%p Debt / Equity Net Debt / Equity 37.6% 30.1% 32.4% 2.3%p -5.2%p 132.8% 127.5% 124.9% 123.1% 121.0% 120.1% 118.7% 116.5% Debt/Equity Net Debt/Equity 37.6% 32.9% 32.8% 32.4% 31.0% 30.1% 26.7% 28.1% 2Q 19 3Q 19 4Q 19 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 8

K-IFRS / Separate 4 CAPEX • CAPEX executed 289.4 bn won in 1Q21 - Access Network 149.7 bn, Backbone Network 34.2 bn, B2B communications 61.1 bn, others 44.4 bn (Unit: KRW bn) Access Network Backbone Network B2B Others 3,313 3,257 2,872 2,514 2,397 2,359 2,250 1,870 1,977 2,199 1,593 1,362 1,133 1,316 1,196 1,035 466 532 452 428 241 408 492 497 448 419 394 517 289 367 362 298 736 305 330 329 284 258 259 227 189 2013 2014 2015 2016 2017 2018 2019 2020 1Q21 9K-IFRS / Separate 4 CAPEX • CAPEX executed 289.4 bn won in 1Q21 - Access Network 149.7 bn, Backbone Network 34.2 bn, B2B communications 61.1 bn, others 44.4 bn (Unit: KRW bn) Access Network Backbone Network B2B Others 3,313 3,257 2,872 2,514 2,397 2,359 2,250 1,870 1,977 2,199 1,593 1,362 1,133 1,316 1,196 1,035 466 532 452 428 241 408 492 497 448 419 394 517 289 367 362 298 736 305 330 329 284 258 259 227 189 2013 2014 2015 2016 2017 2018 2019 2020 1Q21 9

1 1Q21 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix 101 1Q21 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix 10

K-IFRS / Separate 1 KT - Wireless ∙ Wireless service revenue up +2.2% YoY with 5G subscribers growth ∙ Total number of 5G subscribers recorded 4.4 million(30.7% of Handset subscribers) (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Wireless 1,735.7 1,733.4 1,770.7 2.1% 2.0% Service 1,632.4 1,658.5 1,667.6 0.5% 2.2% Interconnection 103.3 74.9 103.1 37.6% -0.2% 22,427 22,333 22,305 22,133 21,922 21,976 21,771 21,549 21,333 1,055 1,419 1,778 2,237 2,812 419 Subscribers 3,617 4,402 (Unit: Thousands) 5G 14,049 14,090 14,124 14,165 14,231 14,324 14,291 14,335 14,364 Handset (5G incl.) (5G incl.) (5G incl.) (5G incl.) (5G incl.) (5G incl.) (5G incl.) (5G incl.) 2nd Device/IoT MVNO 3,069 3,054 3,856 3,985 4,517 3,691 4,100 4,325 3,529 4,994 4,917 3,755 3,768 3,792 3,772 3,645 3,517 3,492 1Q19 2Q19 3Q19 4Q19 1Q20 2Q20 3Q20 4Q20 1Q21 11K-IFRS / Separate 1 KT - Wireless ∙ Wireless service revenue up +2.2% YoY with 5G subscribers growth ∙ Total number of 5G subscribers recorded 4.4 million(30.7% of Handset subscribers) (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Wireless 1,735.7 1,733.4 1,770.7 2.1% 2.0% Service 1,632.4 1,658.5 1,667.6 0.5% 2.2% Interconnection 103.3 74.9 103.1 37.6% -0.2% 22,427 22,333 22,305 22,133 21,922 21,976 21,771 21,549 21,333 1,055 1,419 1,778 2,237 2,812 419 Subscribers 3,617 4,402 (Unit: Thousands) 5G 14,049 14,090 14,124 14,165 14,231 14,324 14,291 14,335 14,364 Handset (5G incl.) (5G incl.) (5G incl.) (5G incl.) (5G incl.) (5G incl.) (5G incl.) (5G incl.) 2nd Device/IoT MVNO 3,069 3,054 3,856 3,985 4,517 3,691 4,100 4,325 3,529 4,994 4,917 3,755 3,768 3,792 3,772 3,645 3,517 3,492 1Q19 2Q19 3Q19 4Q19 1Q20 2Q20 3Q20 4Q20 1Q21 11

K-IFRS / Separate 2 KT – Fixed Line/IPTV ∙ Telephony revenue decline mitigated(YoY -0.3%), Broadband revenue maintained last year’s level despite interconnection rates decrease ∙ IPTV revenue up +6.8% YoY with consistent subs growth and platform revenue growth (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Telephony 378.4 355.1 377.3 6.2% -0.3% Broadband 502.5 503.3 503.2 0.0% 0.1% IPTV 417.7 438.6 446.2 1.7% 6.8% Broadband Subscriber IPTV Subscriber (Unit: Thousands) (Unit: Thousands) 9,276 8,893 9,171 9,130 8,763 9,043 8,687 8,962 8,962 8,904 8,849 8,559 8,422 8,351 8,229 8,113 64.5% 64.1% 63.4% 62.9% 62.1% 61.0% 60.1% 59.0% 2Q19 3Q19 4Q19 1Q20 2Q20 3Q20 4Q20 1Q21 2Q19 3Q19 4Q19 1Q20 2Q20 3Q20 4Q20 1Q21 Subscribers % of GiGA ※ Number of IPTV subscribers above deviates from MSIT’s released figure below following IPTV law - Number of KT pay TV subscriber is 7,588,574 in 1H 2020 (6 month average) 12K-IFRS / Separate 2 KT – Fixed Line/IPTV ∙ Telephony revenue decline mitigated(YoY -0.3%), Broadband revenue maintained last year’s level despite interconnection rates decrease ∙ IPTV revenue up +6.8% YoY with consistent subs growth and platform revenue growth (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY Telephony 378.4 355.1 377.3 6.2% -0.3% Broadband 502.5 503.3 503.2 0.0% 0.1% IPTV 417.7 438.6 446.2 1.7% 6.8% Broadband Subscriber IPTV Subscriber (Unit: Thousands) (Unit: Thousands) 9,276 8,893 9,171 9,130 8,763 9,043 8,687 8,962 8,962 8,904 8,849 8,559 8,422 8,351 8,229 8,113 64.5% 64.1% 63.4% 62.9% 62.1% 61.0% 60.1% 59.0% 2Q19 3Q19 4Q19 1Q20 2Q20 3Q20 4Q20 1Q21 2Q19 3Q19 4Q19 1Q20 2Q20 3Q20 4Q20 1Q21 Subscribers % of GiGA ※ Number of IPTV subscribers above deviates from MSIT’s released figure below following IPTV law - Number of KT pay TV subscriber is 7,588,574 in 1H 2020 (6 month average) 12

K-IFRS / Separate 3 KT – B2B and others ∙ B2B revenue up +2.3% with balanced growth in all sub businesses, AI/DX including IDC/Cloud revenue up +7.5% YoY (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY B2B 668.9 704.3 684.2 -2.8% 2.3% Corporate Fixed Line 267.5 266.8 269.3 0.9% 0.7% Corporate IT/Solution 276.2 308.8 280.4 -9.2% 1.5% AI/DX 125.2 128.6 134.5 4.6% 7.5% Real estate 45.8 50.8 41.3 -18.8% -9.9% Handset revenue 680.1 804.5 751.6 -6.6% 10.5% ※ Most of Bizmeka revenue, which was in AI/DX, transferred to Corp. IT/Solution due to the decision of business termination and reallocation (Retrospectively reflected in revenue of FY2020) B2B business breakdown AI/DX B2B Total IDC, Cloud, AI Platform, Block chain, 20% Corp. IT/Solution AI/DX Smart mobility, etc. 41% Corp. SI, Global ICT, Energy, Video security, 1Q21 Corp. Lines IT/Solution etc. 39% Corp. Lines Line lease, Kornet 13K-IFRS / Separate 3 KT – B2B and others ∙ B2B revenue up +2.3% with balanced growth in all sub businesses, AI/DX including IDC/Cloud revenue up +7.5% YoY (Unit: KRW bn) 1Q20 4Q20 1Q21 QoQ YoY B2B 668.9 704.3 684.2 -2.8% 2.3% Corporate Fixed Line 267.5 266.8 269.3 0.9% 0.7% Corporate IT/Solution 276.2 308.8 280.4 -9.2% 1.5% AI/DX 125.2 128.6 134.5 4.6% 7.5% Real estate 45.8 50.8 41.3 -18.8% -9.9% Handset revenue 680.1 804.5 751.6 -6.6% 10.5% ※ Most of Bizmeka revenue, which was in AI/DX, transferred to Corp. IT/Solution due to the decision of business termination and reallocation (Retrospectively reflected in revenue of FY2020) B2B business breakdown AI/DX B2B Total IDC, Cloud, AI Platform, Block chain, 20% Corp. IT/Solution AI/DX Smart mobility, etc. 41% Corp. SI, Global ICT, Energy, Video security, 1Q21 Corp. Lines IT/Solution etc. 39% Corp. Lines Line lease, Kornet 13

K-IFRS / consolidated(each subsidiary) 4 Major subsidiaries ∙ BC card partly recovered from COVID-19 slump and its revenue grew YoY +5.0% with the increase of credit card transaction ∙ Contents subsidiaries revenue up +12.2% YoY with volume growth in both music distribution and T-Commerce (Unit: KRW bn) Subsidiaries Revenue 1Q20 4Q20 1Q21 QoQ YoY BC card 799.4 856.4 839.5 -2.0% 5.0% Skylife 167.9 176.5 166.9 -5.4% -0.6% Contents subsidiaries 177.9 218.1 199.6 -8.5% 12.2% KT estate 106.7 77.2 62.6 -18.8% -41.3% ※ Contents subsidiaries : Storywiz(2Q20), KT Studio Genie(1Q21) added ※ KT estate : transferred its FM(facility management) unit to KT Telecop in August 2020 OP contribution by subsidiaries in total (Unit: KRW bn) 83.5 89.2 85.5 78.2 47.7 14 1Q20 2Q20 3Q20 4Q20 1Q21K-IFRS / consolidated(each subsidiary) 4 Major subsidiaries ∙ BC card partly recovered from COVID-19 slump and its revenue grew YoY +5.0% with the increase of credit card transaction ∙ Contents subsidiaries revenue up +12.2% YoY with volume growth in both music distribution and T-Commerce (Unit: KRW bn) Subsidiaries Revenue 1Q20 4Q20 1Q21 QoQ YoY BC card 799.4 856.4 839.5 -2.0% 5.0% Skylife 167.9 176.5 166.9 -5.4% -0.6% Contents subsidiaries 177.9 218.1 199.6 -8.5% 12.2% KT estate 106.7 77.2 62.6 -18.8% -41.3% ※ Contents subsidiaries : Storywiz(2Q20), KT Studio Genie(1Q21) added ※ KT estate : transferred its FM(facility management) unit to KT Telecop in August 2020 OP contribution by subsidiaries in total (Unit: KRW bn) 83.5 89.2 85.5 78.2 47.7 14 1Q20 2Q20 3Q20 4Q20 1Q21

1 1Q21 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix 151 1Q21 Highlights 2 Financial Highlights 3 Business Overview 4 Appendix 15

1 K-IFRS Income Statement (Unit: KRW bn) Consolidated 1Q 20 2Q 20 3Q 20 4Q 20 2020 1Q 21 KT Separate 1Q 20 2Q 20 3Q 20 4Q 20 2020 1Q 21 Operating revenue 5,831.7 5,876.5 6,001.2 6,207.3 23,916.7 6,029.4 Operating revenue 4,429.1 4,339.6 4,520.5 4,590.0 17,879.2 4,574.5 Service revenue 5,107.0 5,196.6 5,240.0 5,302.5 20,846.1 5,230.4 Service revenue 3,749.0 3,743.2 3,805.0 3,785.5 15,082.8 3,822.9 Handset revenue 724.7 679.9 761.2 904.7 3,070.5 799.1 Handset revenue 680.1 596.4 715.5 804.5 2,796.5 751.6 Operating expense 5,446.9 5,533.0 5,707.2 6,045.5 22,732.6 5,585.2 Operating expense 4,127.7 4,085.3 4,312.0 4,476.1 17,001.0 4,208.5 Service expense 4,572.5 4,745.7 4,905.7 5,037.5 19,261.4 4,716.8 Service expense 3,367.0 3,442.9 3,569.5 3,610.3 13,989.7 3,443.8 Labor cost 1,003.9 983.7 1,082.3 1,053.8 4,123.7 1,024.2 Labor cost 555.1 535.4 629.2 548.1 2,267.8 569.0 General expense 2,257.7 2,341.6 2,385.3 2,440.5 9,425.1 2,320.7 General expense 1,611.5 1,654.4 1,690.4 1,761.4 6,717.7 1,644.8 Cost of svc provided 759.2 833.0 823.9 860.6 3,276.7 757.4 Cost of svc provided 609.0 617.6 592.6 592.9 2,412.1 584.4 Selling expense 551.6 587.4 614.3 682.6 2,435.8 614.4 Selling expense 591.4 635.5 657.3 707.9 2,592.1 645.6 Cost of device sold 874.4 787.3 801.4 1,008.1 3,471.2 868.5 Cost of device sold 760.8 642.4 742.5 865.7 3,011.5 764.7 Operating income 384.8 343.5 294.0 161.7 1,184.1 444.2 Operating income 301.4 254.3 208.5 114.0 878.2 366.0 N-OP income (loss) -17.0 -34.2 20.1 -178.0 -209.0 24.0 N-OP income (loss) 133.1 -28.2 12.6 -182.5 -64.9 86.3 N-OP income 291.8 87.6 157.8 302.7 839.9 245.0 N-OP income 390.3 84.4 95.6 278.9 849.2 289.3 N-OP expense 305.4 116.8 142.6 502.2 1,067.0 226.7 N-OP expense 257.2 112.5 82.9 461.4 914.1 203.0 Equity Method (G/L) -3.5 -4.8 4.9 21.5 18.0 5.7 Income bf tax 367.8 309.4 314.2 -16.3 975.1 468.2 Income bf tax 434.5 226.2 221.1 - 68.5 813.3 452.2 Income tax 140.6 100.3 84.2 -53.4 271.7 141.7 Income tax 113.8 58.9 58.1 - 83.0 147.8 117.8 Net income 227.2 209.1 229.9 37.2 703.4 326.5 Net income 320.7 167.2 163.0 14.5 665.5 334.4 NI contribution to KT 208.9 178.1 203.3 67.7 658.0 302.6 EBITDA 1,297.2 1,254.7 1,199.3 1,067.1 4,818.4 1,345.3 EBITDA 1,114.9 1,065.4 1,012.3 919.6 4,112.1 1,173.6 EBITDA Margin EBITDA Margin 22.2% 21.4% 20.0% 17.2% 20.1% 22.3% 25.2% 24.6% 22.4% 20.0% 23.0% 25.7% 161 K-IFRS Income Statement (Unit: KRW bn) Consolidated 1Q 20 2Q 20 3Q 20 4Q 20 2020 1Q 21 KT Separate 1Q 20 2Q 20 3Q 20 4Q 20 2020 1Q 21 Operating revenue 5,831.7 5,876.5 6,001.2 6,207.3 23,916.7 6,029.4 Operating revenue 4,429.1 4,339.6 4,520.5 4,590.0 17,879.2 4,574.5 Service revenue 5,107.0 5,196.6 5,240.0 5,302.5 20,846.1 5,230.4 Service revenue 3,749.0 3,743.2 3,805.0 3,785.5 15,082.8 3,822.9 Handset revenue 724.7 679.9 761.2 904.7 3,070.5 799.1 Handset revenue 680.1 596.4 715.5 804.5 2,796.5 751.6 Operating expense 5,446.9 5,533.0 5,707.2 6,045.5 22,732.6 5,585.2 Operating expense 4,127.7 4,085.3 4,312.0 4,476.1 17,001.0 4,208.5 Service expense 4,572.5 4,745.7 4,905.7 5,037.5 19,261.4 4,716.8 Service expense 3,367.0 3,442.9 3,569.5 3,610.3 13,989.7 3,443.8 Labor cost 1,003.9 983.7 1,082.3 1,053.8 4,123.7 1,024.2 Labor cost 555.1 535.4 629.2 548.1 2,267.8 569.0 General expense 2,257.7 2,341.6 2,385.3 2,440.5 9,425.1 2,320.7 General expense 1,611.5 1,654.4 1,690.4 1,761.4 6,717.7 1,644.8 Cost of svc provided 759.2 833.0 823.9 860.6 3,276.7 757.4 Cost of svc provided 609.0 617.6 592.6 592.9 2,412.1 584.4 Selling expense 551.6 587.4 614.3 682.6 2,435.8 614.4 Selling expense 591.4 635.5 657.3 707.9 2,592.1 645.6 Cost of device sold 874.4 787.3 801.4 1,008.1 3,471.2 868.5 Cost of device sold 760.8 642.4 742.5 865.7 3,011.5 764.7 Operating income 384.8 343.5 294.0 161.7 1,184.1 444.2 Operating income 301.4 254.3 208.5 114.0 878.2 366.0 N-OP income (loss) -17.0 -34.2 20.1 -178.0 -209.0 24.0 N-OP income (loss) 133.1 -28.2 12.6 -182.5 -64.9 86.3 N-OP income 291.8 87.6 157.8 302.7 839.9 245.0 N-OP income 390.3 84.4 95.6 278.9 849.2 289.3 N-OP expense 305.4 116.8 142.6 502.2 1,067.0 226.7 N-OP expense 257.2 112.5 82.9 461.4 914.1 203.0 Equity Method (G/L) -3.5 -4.8 4.9 21.5 18.0 5.7 Income bf tax 367.8 309.4 314.2 -16.3 975.1 468.2 Income bf tax 434.5 226.2 221.1 - 68.5 813.3 452.2 Income tax 140.6 100.3 84.2 -53.4 271.7 141.7 Income tax 113.8 58.9 58.1 - 83.0 147.8 117.8 Net income 227.2 209.1 229.9 37.2 703.4 326.5 Net income 320.7 167.2 163.0 14.5 665.5 334.4 NI contribution to KT 208.9 178.1 203.3 67.7 658.0 302.6 EBITDA 1,297.2 1,254.7 1,199.3 1,067.1 4,818.4 1,345.3 EBITDA 1,114.9 1,065.4 1,012.3 919.6 4,112.1 1,173.6 EBITDA Margin EBITDA Margin 22.2% 21.4% 20.0% 17.2% 20.1% 22.3% 25.2% 24.6% 22.4% 20.0% 23.0% 25.7% 16

2 K-IFRS Balance Sheet (Unit: KRW bn) Consolidated 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 KT Separate 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 33,167.9 34,572.2 36,449.2 33,662.5 33,547.6 27,606.1 28,146.8 28,774.1 28,027.9 27,693.7 Assets Assets Current assets 10,881.6 12,474.5 14,211.2 11,154.2 11,567.1 Current assets 6,878.9 7,445.4 8,098.4 7,155.7 7,287.3 Cash & cash equi. 1,627.1 2,942.2 2,990.9 2,634.6 2,753.1 Cash & cash equi. 754.1 1,422.1 1,911.6 1,541.2 1,564.4 Trade & other rec 4,121.3 4,159.9 4,272.5 3,840.2 4,029.5 Trade & other rec 3,490.2 3,372.7 3,473.7 3,127.0 3,353.6 Inventories 634.7 640.6 851.9 534.6 591.9 Inventories 439.4 459.5 649.4 353.3 349.8 Other current asset 4,498.5 4,731.8 6,095.9 4,144.7 4,192.6 Other current asset 2,195.2 2,191.1 2,063.7 2,134.2 2,019.6 -Prepaid_Contract cost 1,362.5 1,378.4 1,379.9 1,345.7 1,310.8 -Prepaid_Contract cost 1,408.2 1,431.6 1,432.8 1,406.9 1,398.9 -Contract assets 393.7 391.2 382.9 392.3 415.8 -Contract assets 359.2 349.7 338.2 343.4 351.1 Non-current assets 22,286.4 22,097.7 22,237.9 22,508.4 21,980.5 Non-current assets 20,727.2 20,701.3 20,675.7 20,872.2 20,406.4 Trade & other rec 996.7 1,123.4 1,060.6 1,128.5 945.3 Trade & other rec 954.4 1,063.8 1,001.3 1,080.3 898.9 Tangible assets 13,497.4 13,454.5 13,773.5 14,206.1 13,877.4 Tangible assets 11,284.6 11,250.6 11,502.2 11,999.7 11,725.9 Other current assets 7,792.3 7,519.8 7,403.8 7,173.7 7,157.8 Other current assets 8,488.2 8,387.0 8,172.2 7,792.2 7,781.6 -Prepaid_Contract cost 461.3 456.9 466.4 458.2 448.2 -Prepaid_Contract cost 448.8 446.0 454.7 454.8 445.1 -Contract assets 147.2 161.6 176.5 194.2 209.4 -Contract assets 93.6 98.6 106.5 118.8 125.6 Liabilities 18,099.2 19,199.7 20,794.0 18,111.1 18,209.7 Liabilities 14,673.1 15,036.5 15,467.8 14,824.4 14,681.3 Current liabilities 9,205.2 9,961.4 11,535.4 9,192.5 9,271.5 Current liabilities 6,520.1 6,613.7 7,037.2 6,608.0 6,563.9 Trade & other payables 6,524.1 6,601.7 8,255.6 6,210.1 5,969.6 Trade & other payables 4,593.9 4,182.5 4,670.0 4,568.4 4,409.4 Short-term borrowings 1,271.3 1,667.3 1,546.0 1,418.1 1,449.0 Short-term borrowings 1,168.5 1,539.3 1,381.4 1,228.8 1,204.5 Others 1,409.9 1,692.4 1,733.8 1,564.3 1,853.0 Others 757.8 891.9 985.9 810.8 950.0 - Contract liabilities 314.6 315.5 316.3 327.1 321.2 - Contract liabilities 316.7 316.0 319.7 316.8 325.0 Non-current liabilities 8,893.9 9,238.3 9,258.6 8,918.6 8,938.2 Non-current liabilities 8,153.0 8,422.8 8,430.5 8,216.4 8,117.4 801.7 811.1 810.0 807.5 690.4 1,567.3 1,570.2 1,530.5 1,512.9 1,206.2 Trade & other payables Trade & other payables Long-term borrowings 6,015.6 6,320.3 6,304.9 5,898.2 6,275.7 Long-term borrowings 5,854.5 6,082.7 6,080.7 5,717.0 5,973.1 Others 2,076.6 2,106.9 2,143.8 2,212.9 1,972.1 Others 731.1 769.9 819.3 986.5 938.1 - Contract liabilities 58.5 51.5 52.2 57.1 50.0 - Contract liabilities 55.5 49.9 50.9 54.6 54.1 Equity 15,068.8 15,372.5 15,655.1 15,551.4 15,337.9 Equity 12,933.0 13,110.2 13,306.3 13,203.5 13,012.4 Retained earnings 11,572.3 11,933.2 12,138.4 12,155.4 12,113.9 Retained earnings 10,916.8 11,083.6 11,247.5 11,233.7 11,221.4 172 K-IFRS Balance Sheet (Unit: KRW bn) Consolidated 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 KT Separate 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 33,167.9 34,572.2 36,449.2 33,662.5 33,547.6 27,606.1 28,146.8 28,774.1 28,027.9 27,693.7 Assets Assets Current assets 10,881.6 12,474.5 14,211.2 11,154.2 11,567.1 Current assets 6,878.9 7,445.4 8,098.4 7,155.7 7,287.3 Cash & cash equi. 1,627.1 2,942.2 2,990.9 2,634.6 2,753.1 Cash & cash equi. 754.1 1,422.1 1,911.6 1,541.2 1,564.4 Trade & other rec 4,121.3 4,159.9 4,272.5 3,840.2 4,029.5 Trade & other rec 3,490.2 3,372.7 3,473.7 3,127.0 3,353.6 Inventories 634.7 640.6 851.9 534.6 591.9 Inventories 439.4 459.5 649.4 353.3 349.8 Other current asset 4,498.5 4,731.8 6,095.9 4,144.7 4,192.6 Other current asset 2,195.2 2,191.1 2,063.7 2,134.2 2,019.6 -Prepaid_Contract cost 1,362.5 1,378.4 1,379.9 1,345.7 1,310.8 -Prepaid_Contract cost 1,408.2 1,431.6 1,432.8 1,406.9 1,398.9 -Contract assets 393.7 391.2 382.9 392.3 415.8 -Contract assets 359.2 349.7 338.2 343.4 351.1 Non-current assets 22,286.4 22,097.7 22,237.9 22,508.4 21,980.5 Non-current assets 20,727.2 20,701.3 20,675.7 20,872.2 20,406.4 Trade & other rec 996.7 1,123.4 1,060.6 1,128.5 945.3 Trade & other rec 954.4 1,063.8 1,001.3 1,080.3 898.9 Tangible assets 13,497.4 13,454.5 13,773.5 14,206.1 13,877.4 Tangible assets 11,284.6 11,250.6 11,502.2 11,999.7 11,725.9 Other current assets 7,792.3 7,519.8 7,403.8 7,173.7 7,157.8 Other current assets 8,488.2 8,387.0 8,172.2 7,792.2 7,781.6 -Prepaid_Contract cost 461.3 456.9 466.4 458.2 448.2 -Prepaid_Contract cost 448.8 446.0 454.7 454.8 445.1 -Contract assets 147.2 161.6 176.5 194.2 209.4 -Contract assets 93.6 98.6 106.5 118.8 125.6 Liabilities 18,099.2 19,199.7 20,794.0 18,111.1 18,209.7 Liabilities 14,673.1 15,036.5 15,467.8 14,824.4 14,681.3 Current liabilities 9,205.2 9,961.4 11,535.4 9,192.5 9,271.5 Current liabilities 6,520.1 6,613.7 7,037.2 6,608.0 6,563.9 Trade & other payables 6,524.1 6,601.7 8,255.6 6,210.1 5,969.6 Trade & other payables 4,593.9 4,182.5 4,670.0 4,568.4 4,409.4 Short-term borrowings 1,271.3 1,667.3 1,546.0 1,418.1 1,449.0 Short-term borrowings 1,168.5 1,539.3 1,381.4 1,228.8 1,204.5 Others 1,409.9 1,692.4 1,733.8 1,564.3 1,853.0 Others 757.8 891.9 985.9 810.8 950.0 - Contract liabilities 314.6 315.5 316.3 327.1 321.2 - Contract liabilities 316.7 316.0 319.7 316.8 325.0 Non-current liabilities 8,893.9 9,238.3 9,258.6 8,918.6 8,938.2 Non-current liabilities 8,153.0 8,422.8 8,430.5 8,216.4 8,117.4 801.7 811.1 810.0 807.5 690.4 1,567.3 1,570.2 1,530.5 1,512.9 1,206.2 Trade & other payables Trade & other payables Long-term borrowings 6,015.6 6,320.3 6,304.9 5,898.2 6,275.7 Long-term borrowings 5,854.5 6,082.7 6,080.7 5,717.0 5,973.1 Others 2,076.6 2,106.9 2,143.8 2,212.9 1,972.1 Others 731.1 769.9 819.3 986.5 938.1 - Contract liabilities 58.5 51.5 52.2 57.1 50.0 - Contract liabilities 55.5 49.9 50.9 54.6 54.1 Equity 15,068.8 15,372.5 15,655.1 15,551.4 15,337.9 Equity 12,933.0 13,110.2 13,306.3 13,203.5 13,012.4 Retained earnings 11,572.3 11,933.2 12,138.4 12,155.4 12,113.9 Retained earnings 10,916.8 11,083.6 11,247.5 11,233.7 11,221.4 17

K-IFRS / Separate 3 Subscribers Wireless 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 QoQ YoY 1) Subscribers (Unit: Thousands) 21,976 22,133 22,333 Total 22,305 22,427 0.5% 2.1% Net additions 55 157 200 -28 122 N/A 123.4% Gross additions 938 1,030 1,033 999 1,165 16.7% 24.2% 2) Deactivation 884 873 833 1,026 1,043 1.7% 18.1% Churn rate 1.3% 1.3% 1.2% 1.5% 1.6% 0.1%p 0.3%p LTE 17,035 16,954 16,774 16,174 15,739 -2.7% -7.6% 1,779 2,237 2,813 5G 3,619 4,404 21.7% 147.6% LTE+5G Penetration rate 85.6% 86.7% 87.7% 88.7% 89.8% 1.1%p 4.2%p 3) ARPU (KRW) 31,773 31,393 31,620 31,946 32,003 0.2% 0.7% Note 1) Subscribers: MSIT’s new guidelines for subscriber disclosure (Retroactively applied from 1Q14, MVNO included) Note 2) Deactivation: Mandatory deactivation included Note 3) ARPU = Wireless revenue* / Wireless subscribers** * Wireless revenue(3G, LTE, 5G, IoT included): Revenue of Voice and Data usage (Interconnection/Subscription fee excluded), VAS, Contract/ Bundled Discounts, and etc. included ** Wireless subscribers: Based on MSIT’s guidelines for average billed subscribers in quarter Fixed Line/IPTV 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 QoQ YoY Subscribers (Unit: Thousands) Telephony 14,033 13,863 13,732 13,582 13,460 -0.9% -4.1% PSTN 10,898 10,736 10,594 10,449 10,311 -1.3% -5.4% VoIP 3,135 3,127 3,138 3,133 3,149 0.5% 0.4% Broadband 8,962 9,043 9,130 9,171 9,276 1.1% 3.5% IPTV (OTV+OTS) 8,422 8,559 8,687 8,763 8,893 1.5% 5.6% ※ Number of IPTV subscribers above deviates from MSIT’s released figure below following IPTV law - Number of KT pay TV subscriber is 7,588,574 in 1H 2020 (6 month average) 18K-IFRS / Separate 3 Subscribers Wireless 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 QoQ YoY 1) Subscribers (Unit: Thousands) 21,976 22,133 22,333 Total 22,305 22,427 0.5% 2.1% Net additions 55 157 200 -28 122 N/A 123.4% Gross additions 938 1,030 1,033 999 1,165 16.7% 24.2% 2) Deactivation 884 873 833 1,026 1,043 1.7% 18.1% Churn rate 1.3% 1.3% 1.2% 1.5% 1.6% 0.1%p 0.3%p LTE 17,035 16,954 16,774 16,174 15,739 -2.7% -7.6% 1,779 2,237 2,813 5G 3,619 4,404 21.7% 147.6% LTE+5G Penetration rate 85.6% 86.7% 87.7% 88.7% 89.8% 1.1%p 4.2%p 3) ARPU (KRW) 31,773 31,393 31,620 31,946 32,003 0.2% 0.7% Note 1) Subscribers: MSIT’s new guidelines for subscriber disclosure (Retroactively applied from 1Q14, MVNO included) Note 2) Deactivation: Mandatory deactivation included Note 3) ARPU = Wireless revenue* / Wireless subscribers** * Wireless revenue(3G, LTE, 5G, IoT included): Revenue of Voice and Data usage (Interconnection/Subscription fee excluded), VAS, Contract/ Bundled Discounts, and etc. included ** Wireless subscribers: Based on MSIT’s guidelines for average billed subscribers in quarter Fixed Line/IPTV 1Q 20 2Q 20 3Q 20 4Q 20 1Q 21 QoQ YoY Subscribers (Unit: Thousands) Telephony 14,033 13,863 13,732 13,582 13,460 -0.9% -4.1% PSTN 10,898 10,736 10,594 10,449 10,311 -1.3% -5.4% VoIP 3,135 3,127 3,138 3,133 3,149 0.5% 0.4% Broadband 8,962 9,043 9,130 9,171 9,276 1.1% 3.5% IPTV (OTV+OTS) 8,422 8,559 8,687 8,763 8,893 1.5% 5.6% ※ Number of IPTV subscribers above deviates from MSIT’s released figure below following IPTV law - Number of KT pay TV subscriber is 7,588,574 in 1H 2020 (6 month average) 18