[Amended] Change of largest shareholder

What happened

AprilBio / Change of largest shareholder / (2026.08.19) Change of largest shareholder

Amendment report (notice) Amendment date: 2026-08-19

1. Disclosure document being amended: Change of largest shareholder 2. Original filing date of the disclosure document being amended: 2026-07-24 3. Reason for amendment: Change to content of "Other matters for investment reference" 4. Amendment items:

Item: 6. Other matters for investment reference - content change Before: "(ii) IMM Scale-up Bio No. 1 LLC funded the total acquisition price (KRW 99,999,976,260) through own funds (KRW 59,999,985,756) and borrowed funds (KRW 39,999,990,504); the lender of the borrowed funds is Shinhan Investment Corp., and the borrowing period runs until the date that is 5 years from July 23, 2026. IMM Scale-up Bio No. 1 LLC plans to establish a root pledge over its dividend-receiving account, the collateral shares (708,000 common shares), and the securities account into which all of its shares in the Company are deposited."

After: "(ii) IMM Scale-up Bio No. 1 LLC funded the total acquisition price (KRW 99,999,976,260) through own funds (KRW 59,999,985,756) and borrowed funds (KRW 39,999,990,504), and entered into a loan funding agreement with Shinhan Investment Corp. as lender, with a borrowing period running until the date that is 5 years from July 23, 2026. Subsequently, on August 19, 2026, Shinhan Investment Corp. transferred, out of its loan receivable from IMM Scale-up Bio No. 1 LLC, KRW 15,000,000,000 to IBK Capital Corporation and KRW 4,999,990,504 to SBI Savings Bank respectively, and transferred to the assignees, with respect to each assigned receivable, all security interests and other rights, obligations and contractual status held as lender. As a result, the holder of the root pledge over the Company's 708,000 common shares changed from Shinhan Investment Corp. alone to Shinhan Investment Corp., IBK Capital Corporation and SBI Savings Bank (joint root pledge), and the holder of the root pledge over the securities account into which all of IMM Scale-up Bio No. 1 LLC's shares in the Company are deposited likewise changed from Shinhan Investment Corp. alone to Shinhan Investment Corp., IBK Capital Corporation and SBI Savings Bank (joint root pledge)."

Change of largest shareholder 1. Details of change Pre-change largest shareholder, etc.: Cha Sang-hoon and 2 others; Shares held (shares): 4,541,000; Ownership ratio (%): 19.39 Post-change largest shareholder, etc.: IMM Healthcare No. 8 LLC and 2 others; Shares held (shares): 5,981,862; Ownership ratio (%): 19.22

2. Reason for change: Change of largest shareholder through acquisition of the former largest shareholder's equity and payment for a third-party placement capital increase - Change due to acquisition of forfeited shares: No - Mandatory holding period for the transferred shares: Yes

3. Purpose of equity acquisition: Simple investment - Funding source: own funds (KRW) 166,999,949,766; borrowed funds (KRW) 87,999,990,504; lender: see "6. Other matters for investment reference"; borrowing period - to -; collateral details: see "6. Other matters for investment reference" - Plan for appointment/dismissal of officers after acquisition: None

4. Date of change: 2026-07-23 5. Date change confirmed: 2026-07-23 6. Other matters for investment reference: - This disclosure reflects the change of largest shareholder resulting from CEO Cha Sang-hoon's performance of the share transfer agreement and the completion of payment for the third-party placement capital increase by IMM Healthcare No. 8 LLC and IMM Scale-up Bio No. 1 LLC. - The pre-change ownership ratio (%) in "1. Details of change" above is calculated on 23,413,826 issued shares, and the post-change ownership ratio (%) on 31,117,877 voting shares issued. The number of voting new shares expected to be issued after completion of payment for the capital increase is 7,704,051 shares. - Details of the funding method for the equity acquisition under "3. Purpose of equity acquisition" are as follows: (i) IMM Healthcare No. 8 LLC funded the total acquisition price (KRW 149,999,977,092) through own funds (KRW 101,999,977,092) and borrowed funds (KRW 48,000,000,000); the lender is TKG Taekwang Co., Ltd., and the borrowing period runs until the date that is 3 months from July 23, 2026. Before the mandatory holding period ends on the Company's 1,663,779 shares provided as collateral for the acquisition financing, IMM Healthcare No. 8 LLC plans to establish a root pledge over the securities account into which those shares are deposited. (ii) IMM Scale-up Bio No. 1 LLC funded the total acquisition price (KRW 99,999,976,260) through own funds (KRW 59,999,985,756) and borrowed funds (KRW 39,999,990,504), entering a loan agreement with Shinhan Investment Corp. as lender for a period running until the date that is 5 years from July 23, 2026. On August 19, 2026, Shinhan Investment Corp. assigned KRW 15,000,000,000 of that loan receivable to IBK Capital Corporation and KRW 4,999,990,504 to SBI Savings Bank, together with the related security interests and contractual status, so that the root pledge holder over the Company's 708,000 collateral shares, and over the securities account holding all of IMM Scale-up Bio No. 1 LLC's Company shares, changed from Shinhan Investment Corp. alone to the three institutions jointly. (iii) IMM Startup Venture Fund No. 2's total acquisition price (KRW 4,999,986,918) was funded entirely with own funds, with no borrowed funds. The above "4. Date of change" and "5. Date change confirmed" are the payment date of the third-party placement capital increase. 1) Of the 1,770,000 shares acquired through the share purchase, the post-change largest shareholder is exempt from the mandatory holding requirement under Article 51 of the KOSDAQ Market Listing Regulations, as an investment vehicle invested in by a private equity fund under Article 47(3)(5) of the Enforcement Rules of the KOSDAQ Market Listing Regulations. - The 8,926,305 new shares (including 1,222,254 non-voting convertible preferred shares) to be issued through the third-party placement capital increase will be subject to a one-year lock-up under Article 2-2(2) of the Regulation on Issuance and Disclosure of Securities, etc. - The largest shareholder of the post-change largest shareholder, IMM Healthcare No. 8 LLC, is IMM Healthcare No. 8 Private Equity Limited Partnership. - The post-change largest shareholder is a corporation established in July 2026; "2. Key financial matters, etc." below is accordingly prepared as of the filing date of this disclosure. - After the change of largest shareholder, management control will be exercised by TKG Huchems pursuant to a joint investment agreement; see the disclosure "Conclusion of agreement concerning change of management control." ※ Related disclosures: 2026-07-23 Conclusion of agreement concerning change of management control; 2026-07-23 Decision on capital increase (third-party placement); 2026-07-23 Decision on capital increase (third-party placement - non-voting convertible preferred shares); 2026-06-25 Decision on capital increase (third-party placement - voting convertible preferred shares)

[Details of change] Name | Relationship | Before: shares/ratio | After: shares/ratio | Note Cha Sang-hoon: Pre-change largest shareholder; Before: 4,425,000 shares / 18.90%; After: 2,655,000 shares / 8.53%; - IMM Healthcare No. 8 LLC: Post-change largest shareholder; Before: 0 / 0.0%; After: 3,085,998 shares / 9.92%; - IMM Scale-up Bio No. 1 LLC: Special related party of post-change largest shareholder; Before: 0 / 0.0%; After: 2,779,458 shares / 8.93%; - IMM Startup Venture Fund No. 2: Special related party of post-change largest shareholder; Before: 0 / 0.0%; After: 116,406 shares / 0.37%; -

[Matters concerning the post-change largest shareholder (where it is a nominal/shell company)] 1. Basic information of the corporation Corporate name: IMM Healthcare No. 8 LLC; Nationality: Republic of Korea; Address: 152 Teheran-ro, Gangnam-gu, Seoul; Corporate registration number: 110114-0040550 Main business: Special purpose company under the Financial Investment Services and Capital Markets Act

- Status of largest shareholder, CEO, representative executive officer and equity information Largest shareholder: IMM Healthcare No. 8 Private Equity Limited Partnership; -; 100% CEO (managing partner): IMM Investment Co., Ltd.; -; -

- Major investors (10% or more) and equity information: - / - / - - Officer career history of largest shareholder, CEO, representative executive officer, major investors: - / - / - / - / - / - / - / - - History as largest shareholder of a listed company: - / - / - / - / - / -

2. Key financial matters, etc. (Unit: KRW million) Fiscal year: 2026, settlement month December Total assets: 102,670; Capital stock: 102,670; Total liabilities: -; Revenue: -; Total equity: 102,670; Net income (loss): - External auditor: Not applicable; Business suspension: No; Audit opinion: Not applicable; Closure of business: No

3. Relationship with the relevant listed company: - / - 4. Transactions in the most recent 3 years: - / - / -