ADDITIONAL INFORMATION AND WHERE
TO FIND IT
In connection with the proposed merger, Everbridge, Inc.
(“Everbridge”) intends to file relevant materials with the Securities and Exchange Commission (the “SEC”), including a preliminary and definitive proxy statement on Schedule 14A. Following the filing of the definitive proxy
statement (the “proxy statement”) with the SEC, Everbridge will mail the proxy statement and a proxy card to each stockholder entitled to vote at the special meeting relating to the proposed merger. BEFORE MAKING ANY VOTING OR INVESTMENT
DECISION, STOCKHOLDERS OF EVERBRIDGE ARE URGED TO CAREFULLY READ THE PROXY STATEMENT IN ITS ENTIRETY (INCLUDING ALL AMENDMENTS AND SUPPLEMENTS THERETO) AND ANY OTHER DOCUMENTS RELATING TO THE PROPOSED MERGER THAT WILL BE FILED WITH THE SEC OR
INCORPORATED BY REFERENCE THEREIN WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED MERGER. Investors and stockholders will be able to obtain copies of the proxy statement (when available) and other
documents filed by Everbridge with the SEC, without charge, through the website maintained by the SEC at https://www.sec.gov. Copies of the documents filed with the SEC by Everbridge will be available free of charge under the SEC Filings
heading of the Investor Relations section of Everbridge’s website ir.everbridge.com.
PARTICIPANTS IN
THE SOLICITATION
Everbridge and its directors and certain of its executive officers, consisting of David
Benjamin, Richard D’Amore, Alison Dean, Rohit Ghai, David Henshall, Kent Mathy, Simon Paris, Sharon Rowlands, who are the non-employee members of the Board of Directors of Everbridge (the
“Board”), and David Wagner, Chief Executive Officer, President and a member of the Board of Directors of Everbridge, and David Rockvam, Executive Vice President, Chief Financial Officer and Treasurer, may be deemed to be participants in
the solicitation of proxies in respect of the proposed merger. Information about its directors and certain of its executive officers, including a description of their direct or indirect interests, by security holdings or otherwise, can be found
under the captions “Security Ownership of Certain Beneficial Owners and Management,” “Executive Compensation,” and “Director Compensation” contained in the proxy
statement for the Everbridge 2023 Annual Meeting of Stockholders filed with the SEC on April 13, 2023 (the “2023 Proxy Statement”) and under Item 5.02 in the current reports on
Form 8-K filed with the SEC on December
20, 2022 and February 5, 2024. To the extent that Everbridge’s directors and executive officers
and their respective affiliates have acquired or disposed of security holdings since the applicable “as of” date disclosed in the 2023 Proxy Statement, such transactions have been or will be reflected on Statements of Change in Ownership
on Form 4 filed with the SEC. Since the “as of” date in the 2023 Proxy Statement, (a) each of Mr. Benjamin and Mr. Ghai received a grant of 5,747 restricted stock units of Everbridge (“RSUs”) that vested
on December 31, 2023 and a grant of 8,068 RSUs that will vest on May 25, 2024 provided that each such director continues to serve on the Board at such date, in addition to any customary
non-equity annual compensation paid to non-employee directors, which consists of an annual cash retainer of $40,000, plus an additional cash retainer per year for
committee membership, (b) Mr. D’Amore had 4,176 RSUs that vested on May 31, 2023, acquired 11,000 shares of common stock of Everbridge (“Common Stock”), and received a grant of 8,068 RSUs that will vest on
May 25, 2024 provided that he continues to serve on the Board at such date, (c) each of Ms. Dean, Mr. Mathy and Ms. Rowlands had 4,176 RSUs that vested on May 31, 2023 and received a grant of 8,068 RSUs that will vest
on May 25, 2024 provided that each such director continues to serve on the Board at such date, (d) Mr. Henshall had 8,331 RSUs that vested on January 31, 2023, had 8,330 RSUs that vested on January 31, 2024,
acquired 20,000 shares of Common Stock on May 30, 2023, and received a grant of 8,068 RSUs that will vest on May 25, 2024 provided that he continues to serve on the Board at such date, (e) Mr. Paris had 1,700 RSUs
that vested on February 28, 2023, had 4,176 RSUs that vested on May 31, 2023, acquired 3,000 shares of Common Stock, and received a grant of 8,068 RSUs that will vest on May 25, 2024 provided that he continues to serve
on the Board at such date, (f) Mr. Wagner had 12,500 RSUs that vested on October 31, 2023, 3,160 of which were withheld by Everbridge to satisfy tax withholding obligations and had 12,500 RSUs that vested on January 31,
2024, 3,431 of which were withheld by Everbridge to satisfy tax withholding obligations and (g) on March 7, 2024, Mr. Rockvam will receive a grant of 115,000 RSUs that will vest over four years with 25% vesting after year one and
quarterly thereafter and a grant of 115,000 performance share units of Everbridge that will vest based on performance measures determined by the Board at the time of grant, 55,000 of which will be forfeited for no consideration upon the
consummation of the proposed merger. In the proposed merger, outstanding equity awards held by Everbridge’s non-employee directors will accelerate vesting prior to the consummation of the proposed merger,
and outstanding equity awards held by Everbridge’s executive officers will be treated in accordance with their respective equity award agreements and as described in the 2023 Proxy Statement under the caption “Executive
Compensation—Everbridge Executive Compensation Program—Potential Payments upon Change in Control.” Stockholders may obtain additional information regarding the interests of such participants by reading the proxy
statement and other relevant materials regarding the proposed merger to be filed with the SEC or incorporated by reference therein when they become available. Investors should read the proxy statement carefully when it becomes available before
making any voting or investment decisions.