Shanghai FourSemi Semiconductor Co., Ltd. (“FourSemi”) has launched its Hong Kong initial public offering, outlining a Global Offering of 12.00 million H shares with an indicative price range of HK$40.00–50.00 per share. At the maximum price, the transaction could raise up to HK$606.05 million (US$77.4 million), excluding any proceeds from the over-allotment option.

Key Offering Details • Structure: 600,000 H shares (5%) allocated to the Hong Kong Public Offering and 11.40 million H shares (95%) to the International Placing, both subject to reallocation. • Over-allotment Option: International underwriters may purchase up to an additional 1.80 million H shares (15% of the base deal), which would lift the total float to 13.80 million shares—equivalent to roughly 1.6% of FourSemi’s post-listing share capital. • Nominal Value: RMB1.00 per H share. • Board Lot & Subscription Cost: Minimum application size is 100 shares; applicants must remit HK$5,050.43 per lot, inclusive of 1.00% brokerage, 0.0027% SFC levy, 0.00565% Stock Exchange trading fee and 0.00015% AFRC levy. • Pricing Date: Final offer price to be set no later than 12:00 noon on 27 March 2026.

Timetable Highlights (Hong Kong Time) • Public offer application window: 9:00 a.m. 23 March 2026 to 12:00 noon 26 March 2026. • Allocation results announcement: on or before 11:00 p.m. 30 March 2026. • Expected listing and commencement of trading: 9:00 a.m. 31 March 2026 under stock code 3625.

Electronic-Only Application The offering adopts a fully digital subscription process. Retail investors may apply via the White Form eIPO platform (www.eipo.com.hk), while professional and institutional investors can instruct brokers or custodians to submit orders through HKSCC’s FINI system. No physical prospectus or paper application channels are provided.

Stabilisation Mechanism Guotai Junan Securities (Hong Kong) Limited will act as stabilising manager and may conduct price-support operations for up to 30 days after the close of the Hong Kong Public Offering (ending 25 April 2026). Stabilisation, if undertaken, will adhere to Hong Kong regulatory requirements and may be terminated at the manager’s discretion at any time within the period.

Listing Conditions The listing is contingent upon final pricing, successful share allocation, and fulfilment of conditions outlined in the prospectus. If any condition is not met, the Global Offering will lapse and application monies will be refunded without interest. H share certificates will be valid at 8:00 a.m. on the listing date, and transactions executed prior to that time carry settlement risk.

FourSemi’s offering is backed by a syndicate led by Guotai Junan Securities (Hong Kong), China International Capital Corporation Hong Kong Securities, UBS, and other joint sponsors, global coordinators, bookrunners and lead managers.