SUPPLEMENT TO THE PROXY STATEMENT FOR
THE SPECIAL MEETING OF STOCKHOLDERS
TO BE HELD JULY 16, 2024
July 8, 2024
As previously
disclosed, on April 26, 2024, U.S. Silica Holdings, Inc., a Delaware corporation (the Company), entered into an Agreement and Plan of Merger (the Merger Agreement), with Star Holding LLC, a Delaware limited
liability company (Parent), and Star Merger Co., a Delaware corporation and a wholly owned subsidiary of Parent (Merger Sub) pursuant to which, among other things, and subject to the terms and conditions set
forth therein, Merger Sub will be merged with and into the Company, with the Company surviving as a wholly owned subsidiary of Parent (the Merger). Parent and Merger Sub are affiliates of certain funds (the Apollo
Funds) managed by affiliates of Apollo Global Management, Inc. On May 24, 2024, the Company filed with the Securities and Exchange Commission (the SEC) a preliminary proxy statement (the Preliminary Proxy
Statement). On June 11, 2024, the Company filed with the SEC a definitive proxy statement (the Definitive Proxy Statement) with respect to the special meeting of the Companys stockholders scheduled to be held
virtually on July 16, 2024 at 9:00 a.m. Central Time in connection with the Merger (the Special Meeting), which the Company first mailed to its stockholders on or about June 11, 2024.
This Schedule 14A (the Schedule) is being filed to update and supplement the Definitive Proxy Statement. The information
contained in this Schedule is incorporated by reference into the Definitive Proxy Statement and should be read in conjunction with the Definitive Proxy Statement, which should be read in its entirety.
In connection with the Merger, fifteen demand letters have been received by the Company sent on behalf of, and two complaints have been filed
on behalf of, purported stockholders of the Company challenging the adequacy of certain disclosures made in the Preliminary Proxy Statement and the Definitive Proxy Statement (collectively, the Stockholder Actions). The two
complaints were both filed in the Supreme Court of the State of New York, County of New York and are captioned Scott v. U.S. Silica Holdings, Inc., et al., Index No. 653236/2024, and Weiss v. U.S. Silica Holdings, Inc., et al., Index
No. 653241/2024, respectively. The Company believes that the allegations in the Stockholder Actions are without merit.
The Company denies
that it has violated any laws or breached any duties to the Companys stockholders, denies all allegations in the Stockholder Actions, and believes no supplemental disclosure to the Definitive Proxy Statement was or is required under any
applicable law, rule or regulation. However, solely to eliminate the burden and expense of potential litigation, to moot certain of plaintiffs disclosure claims, to avoid potential delay or disruption to the Merger, and to provide additional
information to the Companys stockholders, the Company has determined to voluntarily supplement the Definitive Proxy Statement with the below disclosures. The Company believes that the disclosures set forth in the Definitive Proxy Statement
comply fully with applicable law and nothing in the below supplemental disclosures will be deemed an admission of the legal necessity or materiality under applicable law of any of the disclosures set forth herein.
To the extent that information in the below supplemental disclosures differs from, or updates information contained in, the Definitive Proxy
Statement, the information in the below supplemental disclosures will supersede or supplement the information in the Definitive Proxy Statement. Except as otherwise described in the below supplemental disclosures, the Definitive Proxy Statement, the
annexes to the Definitive Proxy Statement and the documents referred to, contained in or incorporated by reference in the Definitive Proxy Statement are not otherwise modified, supplemented or amended.