Notice Regarding Absorption-type merger of Shionogi Pharma Co., Ltd.

OSAKA, Japan, October 27, 2025 - Shionogi & Co., Ltd.  (Head Office: Osaka, Japan; Chief Executive Officer: Isao Teshirogi, Ph.D.; hereafter "Shionogi" or the “Company”) announced that at the Board of Directors meeting held today, it was resolved to merge (hereafter the "Merger") with Shionogi Pharma Co., Ltd. (Head office: Settsu City, Osaka Prefecture; Representative Director and President: Yasuyoshi Iso; hereafter "Shionogi Pharma"), a wholly owned subsidiary of our company, with an effective date of April 1, 2027. Note that the company has omitted some of the disclosure items and details as the Merger is a simplified absorption-type merger of its wholly owned subsidiaries.

1.       Purpose of the merger

Shionogi Pharma is our manufacturing subsidiary responsible for the manufacture of prescription pharmaceuticals and investigational new drugs. Based on our Medium-term Business Plan, SHIONOGI Transformation Strategy 2030 Revision, we are accelerating the globalization and expansion of our business, primarily focused on our in-house discovered infectious disease products. Recently, the environment surrounding the pharmaceutical supply chain has undergone significant changes, including increased geopolitical risks and stricter quality regulations, making global supply chain management even more challenging. Especially, demand for infectious disease drugs can fluctuate significantly depending on the outbreak situation, so flexible responses are essential to ensure a stable supply of necessary medications to patients and healthcare providers. In this environment, it is essential to integrate and collaborate across production, pharmaceutical technology development, sales and marketing, and other functions to build a flexible and resilient production and supply system. The purpose of this absorption-type merger of Shionogi Pharma is to further strengthen these functional collaborations and build a robust production and supply system that can adapt to any environmental changes.

2.       Overview of the merger

(1) Merger schedule

Date of Board Resolution for the merger: October 27, 2025

Date of signing of memorandum of understanding: November, 2025 (planned)

Date of signing of the merger agreement: February, 2027 (planned)

Date of the merger (effective date of the merger): April 1, 2027 (planned)

*Note that this merger falls under the simplified absorption-type split stipulated in Article 796,

Paragraph 2 of the Companies Act for the Company and it falls under a short form merger as prescribed for in Article 784, Paragraph 1 of the Companies Act in relation to Shionogi Pharma. Therefore, the merger agreement will be approved without the approval resolution of the shareholders’ meeting.

(2) Form of merger

This will be an absorption-type merger with Shionogi as the surviving company and Shionogi Pharma as the Absorbed company.

(3) Allocation with merger

As Shionogi Pharma is a wholly owned subsidiary of the Company, there will be no issuance of new shares or allocation of cash or other consideration with this merger.

(4) Handling of stock acquisition rights and bonds with stock acquisition rights associated with the merger

Not applicable.

3.       Outline of merging companies

4.       Situation after the merger

There will be no changes to the Company's trade name, location, representative's title and name, business activities, capital, or fiscal year end following the merger.

5.       Expected effect of the merger on results

As this merger involves the Company and its wholly owned subsidiary, the impact on the Company's consolidated financial results is expected to be minimal.

For Further Information, Contact:

SHIONOGI Website Inquiry Form: https://www.shionogi.com/global/en/contact.html