NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION IN WHOLE OR IN PART IN, INTO OR FROM ANY JURISDICTION WHERE TO DO SO WOULD CONSTITUTE A VIOLATION OF THE RELEVANT LAWS OR REGULATIONS OF SUCH JURISDICTION

16 September 2026

System1 Group PLC (AIM: SYS1)

 ("System1", or “the Company”, or “the Group”)

Rejection of Brave Bison’s Fourth Offer

• Shareholder support to reject the Fourth Offer, including from Lord Ashcroft, Brave Bison’s largest shareholder
• Brave Bison are valuing the Fourth Offer at 360 pence using a 20-day-volume weighted average closing share price of 94 pence on 10 July 2026. Using Brave Bison’s closing share price on 15 September 2026, the value of the Fourth Offer is 328.9 pence
• No increase in the cash consideration. It is still supported by System1’s own significant cash balance (£11.2 million as at 30 August 2026)
• No premium for control; still a discount based on the closing Brave Bison and System1 share prices as at 15 September 2026
• Brave Bison’s Current Trading; unclear on the level of organic growth in the business excluding acquisitions
• Brave Bison strategic rationale remains unclear. System1 would be an independent entity within the enlarged group
• Opportunistic timing: shareholders should continue to reject the Fourth Offer
• System1 Board unanimous and unequivocal rejection of the Fourth Offer

Rupert Howell, Chair of System1 commented: “The Board remains firmly of the view that Brave Bison’s Fourth Offer materially undervalues System1 and is not in the best interests of shareholders. There is no premium for control at today’s prices, no increase in the cash consideration, and, despite Brave Bison’s claims, the offer does not represent 360 pence per share at Brave Bison’s current share price. The reality is that System1 shareholders are being asked to exchange ownership of a high-quality business for an inadequate value.

“The Board also remains unconvinced by Brave Bison’s strategic rationale and believes the Fourth Offer appears driven more by acquisition-led expansion than by any deep strategic fit between the two businesses. System1 shareholders should carefully consider the quality and sustainability of Brave Bison’s own growth.

“At a time when management should be focused on executing our strategy and delivering value, this prolonged and opportunistic approach is wasting management time, causing disruption to the business and incurring unnecessary costs for shareholders. As a Board, we are pleased to have the support of certain of our major shareholders, including Crucible, Lord Ashcroft and BGF, as we unanimously recommend that shareholders continue to reject the Fourth Offer.”

The Board would like to draw shareholders’ attention to a statement made by Lord Ashcroft in Bainsville Commercial Inc’s1 signed letter of intent, dated 15 September 2026 and available at www.system1group.com/investors, which reads:

Lord Ashcroft, c.8% shareholder in System1 commented: “I appreciate that my position as a major shareholder in both Brave Bison and also System1 can cause confusion and I note that certain elements of the media continue to quote me as a backer of Brave Bison when drawing attention to this bid. Therefore, for the sake of clarity, I can confirm that as a holder of c.8% of System1 I have no intention of accepting this wholly inadequate fourth offer.

“From my own dealings with Brave Bison I have questions regarding their Board and despite several requests for improved governance within their business and representation on their Board, my efforts continue to fall on deaf ears. The hypocrisy of how they interact with other boards in their position as a major shareholder does not escape me. In respect to the fourth offer, swapping System1 shares for those in Brave Bison, I would caution all System1 shareholders.”

Reject the Fourth Offer

The Board of System1 (the “Board”) notes the announcement released by Brave Bison Group plc (“Brave Bison”) on 13 September 2026 (and released via the regulatory news service on 14 September 2026) (the “Fourth Offer Announcement”) in relation to its fourth offer for System1 for a revised consideration of 2.394 new Brave Bison shares and 135 pence in cash for each System1 share (the “Fourth Offer”).

Based on Brave Bison’s closing share price of 81.0 pence per share on 15 September 2026, being the last business date before this announcement, the Fourth Offer implies a value of approximately 328.9 pence per System1 share. This represents a discount of 1.8 per cent. to System1’s closing share price of 335.0 pence per share on 15 September 2026, being the last business date before this announcement.

The Board does not see the Fourth Offer or the Alternative Offer as representing an acceptable fair value for all shareholders and, as a result, the Board of System1 unanimously and unequivocally rejects the Fourth Offer and the Alternative Offer.

Further to the response document posted to shareholders on 10 September 2026, the Board reiterates the following points.

Shareholder support to reject the Fourth Offer

The Board confirms that System1 has received new written confirmations from each of its Directors that they have no current intention to accept Brave Bison’s Offer in respect of their own beneficial holdings (or System1 Shares over which they control the voting rights) totalling 1,031,260 System1 Shares, representing in aggregate approximately 8.13 per cent. of System1’s issued ordinary share capital as at 15 September 2026, which includes Crucible Clarity Fund (Lewis Robinson, Non-Executive Director of System1, has an interest in the Company via Crucible Clarity Fund. Crucible Clarity Fund is managed by Crucible Management Limited and Lewis Robinson is on the board of directors that control voting, acceptance and trading decisions).

In addition to the letters of intent received from the System1 Directors, System1 has received updated written confirmations from certain other System1 Shareholders, that they have no current intention of accepting Brave Bison’s Offer in respect of their beneficial holdings totalling 1,872,869 System1 Shares, representing in aggregate approximately 14.76 per cent. of System1’s issued ordinary share capital as at 15 September 2026.

In total, System1 has received written confirmations from certain System1 shareholders, including the Company’s three largest shareholders other than Brave Bison (Bainsville an entity owned and controlled by Lord Ashcroft, Brave Bison’s largest shareholder, BGF and Crucible), who have stated that they have no intention to accept Brave Bison’s Offer in respect of their beneficial holdings totalling 2,904,129 System1 Shares, representing in aggregate approximately 22.89 per cent. of System1’s issued ordinary share capital as at 15 September 2026.

The Board notes the references in the Fourth Offer Announcement in relation to certain System1 shareholder support for the Fourth Offer, representing approximately 10.95 per cent. of the System1 issued share capital. The Board notes that this support comes from only one institutional shareholder, Heritage Capital Management Limited and Heritage Fund Managers Limited with an interest of 2.58 per cent. and then from John Kearon’s former wife (Sarah Kearon) and mother (Heather Kearon); Stefan Barden and family; and Alex Batchelor. The Board notes that John Kearon, Stefan Barden and Alex Batchelor have all been previously employed by System1, as Board directors at various points, but no longer have any operational or executive involvement with the Company.

Value of the Fourth Offer is not 360p based off most recent closing prices

The Board notes Brave Bison’s reference, in both the announcement released by Brave Bison and also in an unauthorised PR post on LinkedIn (that has since been removed to comply with the Takeover Code), to the Fourth Offer representing an implied offer price of 360 pence. Based on Brave Bison’s closing share price of 81.0 pence per share on 15 September 2026, being the last business date before this announcement, the Fourth Offer would imply a value of approximately 328.9 pence per System1 Share. This represents a discount of 1.8 per cent. to System1’s closing share price of 335.0 pence per share on 15 September 2026, being the last business date before this announcement.

Brave Bison’s closing share price on 10 July 2026, prior to the commencement of the offer period, was 90.5 pence The Board notes that since the commencement of the offer period after market close on 10 July 2026, Brave Bison’s share price has decreased by 10.5 per cent. to 81.0 pence, on 15 September 2026, being the last business date before this announcement. Therefore there has been a reduction in the implied value for System1 shareholders.

The Board notes that the Brave Bison Rule 2.7 Announcement and their Fourth Offer announcement continue to use the 20-day-volume weighted average closing share price of Brave Bison of 94 pence on 10 July 2026 (being the last business date before the commencement of the offer period). Shareholders should note that this is not the level at which the Brave Bison shares were trading at that time, as Brave Bison’s closing share price on 10 July 2026 was 90.5 pence. This is a simple attempt to inflate the perceived value of Brave Bison’s offer.

No change to the cash consideration. It is still supported by System1’s own significant cash balance

The Fourth Offer has increased the share consideration but has not increased the cash element which remains at 135 pence per System1 share.

The Fourth Offer implies a cash element in total of approximately £12.4 million, (assuming an issued share capital of 9,155,063, being the System1 Shares subject to the Fourth Offer, excluding the System1 Shares held by Brave Bison, 537,700 treasury shares and any potential additional System1 Shares issued following exercise of options under System1’s Long Term Incentive Plan).

System1’s cash balance at 31 August 2026 was £11.2 million which is closely comparable to the £12.4 million of debt funding required from the Brave Bison debt facility to fully fund the cash element of the Cash and Shares Offer (excluding the System1 Shares held by Brave Bison, 537,700 treasury shares and any potential additional System1 Shares issued following exercise of options under System1’s Long Term Incentive Plan). It could be argued that the cash element of the Brave Bison offer will ultimately be largely funded by System1’s own cash.

No premium for control, still a discount based on the closing Brave Bison and System1 share prices as at 15 September 2026

The Offer is a takeover. It is not a merger where one might expect to see low or no premiums implied from an all share, exchange ratio, type transaction. Brave Bison is offering a combination of cash and its own shares as consideration for your System1 Shares. If a company is acquiring control of another company that will enable the acquirer to benefit from synergies from the acquisition, then it is customary that an acquirer should pay a control premium for that benefit.

The Offer does not provide any premium for the control of System1. An offer made without a notable premium to the current share price is not customary and does not provide all System1 Shareholders with a suitable premium for control.

Using the most recent closing prices for Brave Bison and System1, the Fourth Offer is being made at a discount to the current value of your System1 Shares no matter how Brave Bison presents it.

Brave Bison’s Current Trading, unclear on the level of organic growth in the business excluding acquisitions

The System1 Board notes the section within Brave Bison’s Fourth Offer announcement “Brave Bison Current Trading”. The Board has previously noted that Brave Bison’s organic growth is unclear as they do not separately disclose the performance excluding the impact of acquisitions made in any given financial year.

The Board notes that Brave Bison’s H1 2026 financial highlights do not separately disclose the full impact of acquisitions. This makes it difficult to determine whether the underlying Brave Bison Group, excluding acquisition/s made in any given financial year, is actually organically growing revenue or profit.

Brave Bison’s Fourth Offer announcement commented on System1’s recent trading update for the 5-month period ended 31 August 2026.  It noted that “shareholders should note that those expectations imply revenue growth of only 5 per cent. compared with FY26 and only four per cent. compared with FY25 over a two-year period.”.  If this is an attempt by Brave Bison to compare its financial performance with System1s then System1 Shareholders should be aware that System1 is actually growing organically. It is unclear if the same can be said of Brave Bison after you remove the impact of their most recent acquisitions. The Board believes this is important as System1 Shareholders consider the Fourth Offer which has marginally increased the amount of Brave Bison shares being offered as consideration. 

System1 Board support to Reject the Fourth Offer

System1 has received updated written confirmations from each Director that they have no current intention to accept Brave Bison’s Offer in respect of their own beneficial holdings (or System1 Shares over which they control the voting rights) totalling 1,031,260 System1 Shares, representing in aggregate approximately 8.13 per cent. of System1’s issued ordinary share capital as at 15 September 2026 as follows:

Note:

1.       Percentages are calculated on the basis of 12,689,073 System1 Shares (excluding Treasury Shares) in issue as at 15 September 2026 and rounded to two decimal places.
2.       Lewis Robinson has an interest in the Company via Crucible Clarity Fund. Crucible Clarity Fund is managed by Crucible Management Limited and Lewis Robinson is on the board of directors that control voting, acceptance and trading decisions.

System1 Shareholder support to Reject the Fourth Offer

In addition to the letters of intent received from the System1 Directors, System1 has received written confirmations from certain other System1 Shareholders that they have no current intention to accept Brave Bison’s Offer in respect of their beneficial holdings totalling 1,872,869 System1 Shares, representing in aggregate approximately 14.76 per cent. of System1’s issued ordinary share capital as at 15 September 2026 as follows:

Note:

1.       Percentages are calculated on the basis of 12,689,073 System1 Shares (excluding Treasury Shares) in issue as at 15 September 2026 and rounded to two decimal places

2.       Bainsville Commercial Inc is owned and controlled by Lord Ashcroft
3.       James Gregory’s wife.

Brave Bison strategic rationale remains unclear

Brave Bison has stated that System1 will form a newly established Marketing Effectiveness division within Brave Bison. System1 will in effect be a standalone business within Brave Bison.

Brave Bison has stated the following:

• that the System1 Board has acknowledged the strong underlying industrial logic in combining two already connected marketing technology companies. The Board acknowledges there are benefits that can be achieved by having increased scale and with the removal of certain central costs but notes that these benefits are likely to be limited in the proposed combination with Brave Bison as System1 would be a standalone business within the Enlarged Group. The Board believes this is different to strategic rationale as Brave Bison does not have a marketing effectiveness platform and the Board believes there is limited commercial overlap in the two businesses’ offering.

• that the combination of Brave Bison and System1 would enable decisive investment to compete against well-resourced rivals. The Board notes that System1 has a strong cash balance and is able to make investments in growth without being part of Brave Bison.

• that the combined financial firepower and infrastructure would accelerate product development and support attracting and retaining world-class talent. The Board believes System1 can do this effectively without being owned by Brave Bison.

• that the Enlarged Group would benefit from the combined scale, capital and talent base to enable decisive investment in AI capabilities. The Board believes that its standalone AI strategy is capable of delivering the benefits independently.

The Board is unclear about the merits of the strategic rationale of Brave Bison acquiring System1. This is different to the industrial logic that Brave Bison sets out around scale. The Board accepts that the Enlarged Group would be larger than Brave Bison is currently, and there would be the removal of some duplication of certain head office roles and functions and other costs which is typical in sectoral financial rollups. However, this does not feel strategic nor reflective of an ability to accelerate growth. The Board also notes that there are no statements from Brave Bison that would suggest that they would look to support System1’s growth or that they would seek to introduce one or more of System1’s products to Brave Bison’s customers who are not currently System1 customers.

Opportunistic timing: shareholders should continue to reject the Fourth Offer

Brave Bison acquired its approximate 28 per cent. holding in System1, in large part from System1’s former founder, John Kearon. at an average in price of 242 pence per System1 Share. The timing for this acquisition of System1 Shares was well placed on 2 March 2026, not long before the announcement of System1’s improved trading and outlook on 16 March 2026.

Since becoming System1’s largest shareholder, Brave Bison has had certain access to information and diligence via the relationship agreement we put in place. Brave Bison can see the underlying improvements and activity in the business. The trading update announced on 10 September 2026 highlights improved revenues and positive trading.

The Board believes the Fourth Offer and the Alternative Offer continue to be opportunistic and do not reflect the underlying momentum in the business or its wider strategic value.

Alternative Offer

The Board also notes the all-share offer, comprising 3.36 Brave Bison shares for each System1 share (the “Alternative Offer”). The Alternative Offer, based on Brave Bison’s closing share price of 81.0 pence on 15 September 2026, being the last business date before this announcement, implies a value of 272.2 pence for each System1 share. This represents a discount of 18.8 per cent. to System1’s closing share price of 335.0 pence per share on 15 September 2026, being the last business date before this announcement.

Capitalised terms used but not defined in this announcement have the meanings given to them in the Response Document.

Further information on the Company can be found at www.System1group.com.

For further information, please contact:

Disclosure requirements of the Code

Under Rule 8.3(a) of the Code, any person who is interested in 1% or more of any class of relevant securities of an offeree company or of any securities exchange offeror (being any offeror other than an offeror in respect of which it has been announced that its offer is, or is likely to be, solely in cash) must make an Opening Position Disclosure following the commencement of the offer period and, if later, following the announcement in which any securities exchange offeror is first identified. An Opening Position Disclosure must contain details of the person’s interests and short positions in, and rights to subscribe for, any relevant securities of each of (i) the offeree company and (ii) any securities exchange offeror(s). An Opening Position Disclosure by a person to whom Rule 8.3(a) applies must be made by no later than 3.30 pm (London time) on the 10th business day following the commencement of the offer period and, if appropriate, by no later than 3.30 pm (London time) on the 10th business day following the announcement in which any securities exchange offeror is first identified. Relevant persons who deal in the relevant securities of the offeree company or of a securities exchange offeror prior to the deadline for making an Opening Position Disclosure must instead make a Dealing Disclosure.

Under Rule 8.3(b) of the Code, any person who is, or becomes, interested in 1% or more of any class of relevant securities of the offeree company or of any securities exchange offeror must make a Dealing Disclosure if the person deals in any relevant securities of the offeree company or of any securities exchange offeror. A Dealing Disclosure must contain details of the dealing concerned and of the person’s interests and short positions in, and rights to subscribe for, any relevant securities of each of (i) the offeree company and (ii) any securities exchange offeror(s), save to the extent that these details have previously been disclosed under Rule 8. A Dealing Disclosure by a person to whom Rule 8.3(b) applies must be made by no later than 3.30 pm (London time) on the business day following the date of the relevant dealing.

If two or more persons act together pursuant to an agreement or understanding, whether formal or informal, to acquire or control an interest in relevant securities of an offeree company or a securities exchange offeror, they will be deemed to be a single person for the purpose of Rule 8.3.

Opening Position Disclosures must also be made by the offeree company and by any offeror and Dealing Disclosures must also be made by the offeree company, by any offeror and by any persons acting in concert with any of them (see Rules 8.1, 8.2 and 8.4).

Details of the offeree and offeror companies in respect of whose relevant securities Opening Position Disclosures and Dealing Disclosures must be made can be found in the Disclosure Table on the Takeover Panel’s website at www.thetakeoverpanel.org.uk, including details of the number of relevant securities in issue, when the offer period commenced and when any offeror was first identified. You should contact the Panel’s Market Surveillance Unit on +44 (0)20 7638 0129 if you are in any doubt as to whether you are required to make an Opening Position Disclosure or a Dealing Disclosure.

Rule 2.9 information

In accordance with Rule 2.9 of the Code, System1 confirms that as at the date of this announcement, its issued share capital (excluding 537,700 ordinary shares held in treasury) consisted of 12,689,073 ordinary shares of 1 pence each carrying voting rights of one vote per share. The ISIN reference number for these securities is GB00B1GVQH21 and the Company's LEI number is 213800TDLR42C3Q9ZB74.

Publication on website

In accordance with Rule 26.1 of the Code, a copy of this announcement will be available on the website of System1 at www.System1group.com/investors promptly and by no later than 12 noon (London time) on the business day following this announcement. The content of the websites referred to in this announcement are not incorporated into and do not form part of this announcement.

Market Abuse Regulation

The information contained within this announcement is considered to constitute inside information as stipulated under Article 7 of the Market Abuse Regulations (EU) No.596/2014 as incorporated into UK domestic law by virtue of the European Union (Withdrawal) Act 2018, as amended. Upon the publication of this announcement via a regulatory information service, this inside information will be considered to be in the public domain.

The person responsible for arranging the release of this announcement on behalf of System1 is Chris Willford.

Other notices

This announcement is not intended to, and does not, constitute or form part of any offer, invitation or the solicitation of an offer to purchase, otherwise acquire, subscribe for, sell or otherwise dispose of, any securities whether pursuant to this announcement or otherwise, or the solicitation of any vote in favour or approval of any offer in any jurisdiction where to do so would constitute a violation of the laws of such jurisdiction and any such offer (or solicitation) may not be extended in any such jurisdiction.

This announcement has been prepared in accordance with English law and the Code, and information disclosed may not be the same as that which would have been prepared in accordance with laws outside of the United Kingdom. The distribution of this announcement in jurisdictions outside the United Kingdom may be restricted by law and therefore persons into whose possession this announcement comes should inform themselves about, and observe, such restrictions. Any failure to comply with the restrictions may constitute a violation of the securities law of any such jurisdiction.

Canaccord Genuity Limited (“Canaccord Genuity”), which is authorised and regulated in the United Kingdom by the Financial Conduct Authority, is acting exclusively for System1 and for no-one else in connection with the matters referred to in this Announcement and will not be responsible to any person other than System1 for providing the protections afforded to clients of Canaccord Genuity, nor for providing advice in relation to the matters referred to herein. Neither Canaccord Genuity nor any of its affiliates (nor any of its or their respective directors, officers, employees, representatives or agents) owes or accepts any duty, liability or responsibility whatsoever (whether direct or indirect, whether in contract, in tort, under statute or otherwise) to any person who is not a client of Canaccord Genuity in connection with the matters referred to in this Announcement, or otherwise.

APPENDIX

SOURCES OF INFORMATION AND BASES OF CALCULATION

In this announcement, unless otherwise stated or the context otherwise requires, the following sources and bases have been used:

1. All references to System1 Shares are to System1 ordinary shares of £0.01 each.
2. Unless stated otherwise, all prices quoted for System1 Shares are Closing Prices derived from Bloomberg.
3. Volume weighted average prices are derived from Bloomberg.
4. Certain figures included in this document have been subject to rounding adjustments.
5. Unless otherwise stated, the financial information relating to System1 is extracted from the annual report and accounts of Signal for the relevant years, and the audited consolidated financial statements contained therein have been prepared in compliance with United Kingdom accounting standards, including IFRS and the Companies Act.
6. Net cash as at 31 August 2026 was £11.2 million.