Rights Offering Amendment: 1st Issue Price Set at KRW 4,125

Material Event Report (Rights Offering Decision) 6.3 LB Semicon Co., Ltd. Amendment Filing (Report) June 17, 2026 1. Subject of amendment: Material Event Report (Rights Offering Decision) 2. Original filing date: May 15, 2026 3. Amendment items * This amendment to the Material Event Report reflects revisions following the determination of the 1st issue price. Amended items are indicated in bold blue. | Item | Reason for amendment | Before | After | |---|---|---|---| | 4. Purpose of fundraising - Working capital | Revision following determination of 1st issue price | 19,800,000,000 | 19,500,000,000 | | 6. New share issue price - Indicative price | | 4,150 | 4,125 | Material Event Report / Exchange Filing Obligation To: Financial Services Commission / Korea Exchange June 17, 2026 Company name: LB Semicon Co., Ltd. CEO: Lee Dae-gyo Head office: 138 Cheongbuk Sandan-ro, Cheongbuk-eup, Pyeongtaek-si Tel: 031-680-1600 Website: http://www.lbsemicon.com Responsible officer: Kim Jeong-gyu, Head of Management Administration Division Rights Offering Decision 1. Type and number of new shares - Common stock (shares): 12,000,000 - Other shares (shares): - 2. Par value per share (KRW): 500 3. Total shares outstanding before issuance - Common stock: 58,083,006 - Other shares: - 4. Purpose of fundraising - Facility investment funds (KRW): 30,000,000,000 - Business acquisition funds: - - Working capital (KRW): 19,500,000,000 - Debt repayment funds: - - Other corporate securities acquisition funds: - - Other funds: - 5. Method of capital increase: Allocation to existing shareholders followed by public offering of forfeited shares 6. New share issue price - Determined issue price - Common stock: - - Indicative price - Common stock: KRW 4,125 (final determination date: July 24, 2026) 7. Issue price calculation method: See Item 24 (a) Calculation method of new share issue price 8. Record date for new share allocation: June 19, 2026 9. Number of new shares allocated per share: 0.2066008773 10. ESOP preferential allocation ratio: - 11. Subscription dates - ESOP: - - Existing shareholders: July 29-30, 2026 12. Payment date: August 6, 2026 13. Plan for forfeited shares: See Item 24 (b) 14. Dividend reference date for new shares: January 1, 2026 15. Scheduled share certificate issuance date: - 16. Scheduled listing date of new shares: August 21, 2026 17. Lead underwriter: KB Securities Co., Ltd. 18. Transferability of preemptive rights: Yes - Listing of preemptive right certificates: Yes - Financial investment company handling trading/brokerage of preemptive right certificates: KB Securities 19. Board resolution date: May 15, 2026 - Outside directors: 1 attended, 0 absent - Auditor (audit committee member) attendance: Yes 20. Securities registration statement filing required: Yes 22. Short-sale prohibition period for subscribers: Yes, May 18, 2026 - July 24, 2026 23. Subject to FTC notification: Not applicable 24. Other matters for investment consideration (a) New share issue price calculation method 1) Indicative issue price: Calculated based on the trading day immediately preceding the board resolution (May 14, 2026), using the lower of (i) the arithmetic average of 1-month, 1-week, and base-date volume-weighted average prices on KOSDAQ and (ii) the base-date VWAP, as the reference price, with a 20% discount applied per the formula: Indicative issue price = Reference price x (1 - discount) / [1 + (capital increase ratio x discount)]. Rounded up to tick size; if below par, par value applies. 2) 1st issue price: Calculated using the same methodology with the base date being the 3rd trading day before the new share allocation record date, 20% discount applied. 3) 2nd issue price: Based on the 3rd trading day before the first day of existing-shareholder subscription, using the lower of (i) the arithmetic average of 1-week and base-date VWAP and (ii) the base-date VWAP, with a 20% discount. Formula: 2nd issue price = Reference price x (1 - discount). 4) Final issue price: The lower of 1st and 2nd issue prices. However, pursuant to Article 165-6 of the Financial Investment Services and Capital Markets Act and Article 5-15-2 of the Securities Issuance and Disclosure Regulations, if this is lower than the price calculated by applying a 40% discount to the VWAP of the 3rd-5th trading days before subscription, that 40%-discounted price becomes the final issue price. Formula: Final issue price = MAX[MIN(1st issue price, 2nd issue price), 60% of reference price]. 5) The final issue price will be determined on the 3rd trading day before the first day of existing-shareholder subscription and disclosed via DART on July 27, 2026; also announced on the company website (www.lbsemicon.com) in lieu of individual notification. (b) Allocation method 1) Existing shareholder subscription (preemptive right certificate subscription): Shareholders on record as of 18:00 on the new share allocation record date (June 19, 2026 scheduled) receive 0.2066008773 shares per held share (fractions discarded), with allocation up to the subscription quantity within the allocated amount. Allocation per share may change due to treasury share movements before the record date. 2) Excess subscription: Any forfeited or fractional shares after existing-shareholder subscription may be allocated to existing shareholders/preemptive right certificate holders who excess-subscribed (excess ratio: 0.2 shares per allocated new share), proportionally; fractions discarded. If excess subscriptions fall short of forfeited/fractional shares, 100% allocated. (i) Subscription cap = preemptive right subscription cap + excess subscription cap (ii) Preemptive right subscription cap = number of preemptive right certificates held (iii) Excess subscription cap = preemptive right subscription cap x 20% 4) Public offering subscription: Forfeited and fractional shares from the existing-shareholder and excess subscriptions ("public offering portion") will be publicly offered by the lead underwriter as follows. Pursuant to Article 9-2-3 and 9-2-4 of the Securities Underwriting Business Regulations, at least 10% of the offered shares will be allocated to high-risk high-yield investment trusts, and at least 30% to venture business investment trusts. The remaining 60% will be allocated to individual subscribers and institutional investors (including collective investment business operators) without distinction. If any group is undersubscribed, those shares will be reallocated to oversubscribed groups. [Translation truncated]