Extension of Broker Option & Subscription

Extension of Broker Option

Subscription

Mendell Helium announces that, further to its announcement of 17 November 2025 regarding the Subscription, Issue of Equity and Warrants (the "November Subscription Announcement"), it has received expressions of interest from investors to participate in the broker option (the "Broker Option"). To provide time for these investors to finalise their commitments, the Company has agreed with AlbR Capital Limited ("AlbR") to extend the period during which the Broker Option may be exercised. If all of the proposed investors participate then the Broker Option is expected to be exercised in full. Pending conclusion of these discussions, Mendell Helium also announces that it has received a further subscription for new ordinary shares on the same terms as the Subscription described in that announcement from an existing shareholder.

As announced on 27 June 2024, the Company has an option (the "Option") to acquire M3 Helium, a producer of helium which is based in Kansas and holds an interest in six producing wells. There is no certainty that the Company's option to acquire M3 Helium will be exercised, nor that the enlarged group will successfully complete a re-admission. As announced on 1 December 2025, the Company and M3 Helium have agreed to extend the date on which the Option should be exercised to 28 February 2026.

Extension of Broker Option

As set out in the November Subscription Announcement, the Company granted AlbR, the Broker Option over up to 10,000,000 new ordinary shares (the "Broker Option Shares"), exercisable at the Issue Price and originally exercisable up to 4.30 p.m. (UK time) on 24 November 2025.

The Company has agreed with AlbR that the latest time and date for the exercise of the Broker Option will be extended and that the Broker Option will be exercisable, at AlbR's discretion (following consultation with the Company), on one or more occasions up to 4.30 p.m. (UK time) on 8 December 2025.

All other terms of the Broker Option remain unchanged.

Additional Subscription

Pursuant to the terms of the Subscription set out in the November Subscription Announcement, the Company has raised approximately an additional £600 through the issue of 20,000 new ordinary shares of 1 pence each in the Company ("Ordinary Shares") at an issue price of 3 pence per new Ordinary Share (the "Issue Price") (the "Additional Subscription").

The Additional Subscription, consistent with the Subscription, has been carried out directly by the Company without the payment of commissions.

As with the Subscription described in the November Subscription Announcement, for every two new Ordinary Shares issued pursuant to the Additional Subscription, investors will receive:

• one warrant to subscribe for an additional new ordinary share in the Company at an exercise price of 4.5 pence per share; and
• one warrant to subscribe for an additional new ordinary share in the Company at an exercise price of 6 pence per share,

each exercisable within two years of Admission of the relevant Ordinary Shares. In aggregate, 20,000 additional warrants will be issued pursuant to the Additional Subscription on this basis.

Admission

Application will be made for the 20,000 new Ordinary Shares to be admitted to trading on the Aquis Stock Exchange AQSE Growth Market ("Admission"). Admission is expected to occur at 8:00 a.m. on or around 10 December 2025. The new Ordinary Shares will rank pari passu with the existing Ordinary Shares.

Total Voting Rights

Following Admission, the Company's enlarged share capital will comprise 123,257,973 Ordinary Shares of 1 pence each. Therefore, the total number of voting rights in the Company will be 123,257,973. This figure may be used by shareholders as the denominator for calculations by which they will determine if they are required to notify their interest in the Company, or a change to their interest in the Company, under the Financial Conduct Authority's Disclosure Guidance and Transparency Rules.

Overview of M3 Helium

Mendell Helium announced on 27 June 2024 that it has entered into an option agreement to acquire the entire issued share capital of M3 Helium through the issue of 57,611,552 new ordinary shares in Mendell Helium to M3 Helium's shareholders. The exercise of the option will constitute a reverse takeover pursuant to AQSE Rule 3.6 of the Access Rule Book and is subject to, inter alia, publication of an admission document.

M3 Helium's flagship well, Rost 1-26, is in Fort Dodge, just to the east of Dodge City, Kansas. It has been tested as containing 5.1% helium composition and a drill stem test yielded a maximum flow rate of approximately 2,900 Mcf per day. M3 Helium owns a mobile Pressure Swing Adsorption production plant which has been installed on site and will be used to purify the produced helium. The plant is capable of processing up to 800 Mcf per day of raw gas and purifying it up to 99.999% helium although management believes on-site purification to around 75% will be more practical.

Water removed from Rost 1-26 is delivered to Brobee, a nearby disposal well that has been permitted at 5,000 barrels of water per day at 1,200 psi.

Production at Rost 1-26 commenced in early November 2025.