[Amended] Supply contract signed (voluntary)

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SGC E&C / Supply Contract Signed (Voluntary Disclosure) / (2026.08.14)

Supply Contract Signed (Voluntary Disclosure)

Amendment Report (Correction) Amendment date: 2026-08-14

1. Disclosure document being amended: Supply Contract Signed 2. Submission date of the disclosure document being amended: 2024-08-27 3. Reason for amendment: Change in end date

4. Amended items Item: 5. Contract period - End date Before amendment: 2026-10-31 After amendment: 2026-11-30

Item: 6. Main contract terms - Existence of contract deposit/advance payment; Payment terms, etc. Before amendment: - After amendment: Yes; - Advance payment: 10%; - Progress payment: 90%

Supply Contract Signed (Voluntary Disclosure)

1. Details of the sale/supply contract: PDH/PP EPC Package (construction of propylene/polypropylene production facilities)

2. Contract details Whether this is a conditional contract: Not applicable Confirmed contract amount: 113,499,709,111 Conditional contract amount: - Total contract amount (KRW): 113,499,709,111 Most recent revenue (KRW): 1,863,679,592,064 Ratio to revenue (%): 6.1

3. Contract counterparty Name: AL-WAHA Petrochemical Company Most recent revenue (KRW): 520,049,580,000 Main business: Production and sale of polypropylene Relationship with the Company: - Performance of similar contracts with the Company in the last 3 years: Not applicable

4. Sales/supply region: Location designated by the ordering party

5. Contract period Start date: 2024-07-01 End date: 2026-11-30

6. Main contract terms Existence of contract deposit/advance payment: Yes Payment terms, etc.: - Advance payment: 10%; - Progress payment: 90%

7. Sales/supply method Self-production: Not applicable Outsourced production: Applicable Other: -

8. Contract (order) date: 2024-08-26

9. Other matters for investment reference 1. The contract amount in item 2 above excludes VAT, and "most recent revenue" is based on the K-IFRS consolidated financial statements for 2023. 2. This is an EPC project in which the Company performs engineering and procurement (EP) and the Company's subsidiary performs construction (C); the Company's Saudi Arabian subsidiary (SGC Arabia Co., Ltd.) entered into the construction (C) contract for this project on August 26, 2024, with details as follows: - Head office contract portion: KRW 113,499,709,111 (USD 85,731,331) - Saudi Arabian subsidiary contract portion: KRW 110,261,063,997 (SAR 312,504,787) * The exchange rate applied to the head office contract portion of USD 85,731,331 is the first-quoted basic exchange rate on August 27 (KRW 1,323.90). * The exchange rate applied to the Saudi Arabian subsidiary contract portion of SAR 312,504,787 is the first-quoted basic exchange rate on August 27 (KRW 352.83). 3. The contract period (start date) in item 5 above is based on the effective date under the contract as agreed with the counterparty. 4. The above contract details may change in accordance with the terms specified in the construction contract and the business progress schedule.

* Related disclosures: -