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 OF SUCH JURISDICTION

12 September 2025

Spirent Communications plc ("Spirent" or "the Company")

Rule 2.9 Announcement

In accordance with Rule 2.9 of the City Code on Takeovers and Mergers (the "Code"), the Company confirms that, as at the time of this announcement on Friday, 12 September, it had in issue 589,797,890 ordinary shares of 3 & 1/3 pence each with ISIN number GB0004726096. The Company holds no shares in treasury.

The Company has a sponsored Level 1 American Depositary Receipts ("ADR") programme for which BNY Mellon acts as Depositary. One ADR represents four ordinary shares of the Company. The ADRs trade on the US over-the-counter (OTC) market under the symbol SPMYY. The CUSIP number is 4856M209 and the ISIN is US84856M2098.

The total number of shares attracting voting rights in the Company is therefore 589,797,890.

The above figure may be used by shareholders to determine the percentage of issued share capital they hold in the Company and if they are required to notify their interest in, or a change to their interest in, the Company under the FCA's Disclosure Guidance and Transparency Rules.

Defined terms used but not defined in this announcement have the meanings set out in the scheme document published by Spirent dated 25 April 2024 in relation to the recommended acquisition of the entire issued and to be issued share capital of Spirent by Keysight Technologies, Inc.

Enquiries:

Linklaters LLP is retained as legal adviser to the Company.

Important Notices

N.M. Rothschild & Sons Limited ("Rothschild & Co"), which is authorised and regulated by the Financial Conduct Authority in the United Kingdom, is acting exclusively as financial adviser to Spirent and no one else in connection with the Acquisition and the Scheme and will not be responsible to anyone other than Spirent for providing the protections afforded to clients of Rothschild & Co nor for providing advice in connection with the Acquisition or the Scheme or any matter referred to herein. Neither Rothschild & Co nor any of its affiliates (nor their respective directors, officers, employees 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 Rothschild & Co in connection with this announcement, any statement contained in this announcement, the Spirent Acquisition, the Scheme or otherwise. No representation or warranty, express or implied, is made by Rothschild & Co as to the contents of this announcement.

UBS AG London Branch ("UBS") is authorised and regulated by the Financial Market Supervisory Authority in Switzerland. It is authorised by the Prudential Regulation Authority and subject to regulation by the Financial Conduct Authority and limited regulation by the Prudential Regulation Authority in the United Kingdom. UBS is acting exclusively as financial adviser and corporate broker to Spirent and no one else in connection with the Acquisition and the Scheme. In connection with such matters, UBS will not regard any other person as its client, nor will it be responsible to any other person for providing the protections afforded to its clients or for providing advice in relation to the Acquisition, the Scheme, the contents of this announcement or any other matter referred to herein.

Jefferies International Limited ("Jefferies") is authorised and regulated in the UK by the Financial Conduct Authority. Jefferies is acting exclusively as financial adviser and corporate broker to Spirent and no one else in connection with the Acquisition and the Scheme, and will not be responsible to anyone other than Spirent for providing the protections afforded to clients of Jefferies, nor for providing advice in connection with the Acquisition or Scheme or any matter referred to herein. Neither Jefferies nor any of its affiliates (nor their respective directors, officers, employees 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 Jefferies in connection with this announcement, any statement contained in this announcement, the Acquisition or Scheme or otherwise. No representation or warranty, express or implied, is made by Jefferies as to the contents of this announcement.

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 http://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.