This filing relates solely to preliminary communications made before the commencement of a
planned tender offer (the “Offer”) by Liberty Acquisition Sub Inc., a Delaware corporation (“Merger Sub”), an indirect wholly owned subsidiary of Global Infrastructure Solutions Inc., a Delaware corporation
(“GISI”), for all of the outstanding shares of common stock, par value $0.0001 per share (the “Common Stock”), of Hill International, Inc., a Delaware corporation (“Hill”), to be commenced pursuant
to the Agreement and Plan of Merger, dated as of August 16, 2022 (the “Merger Agreement”), by and among the Company, Merger Sub and GISI.
Additional Information and Where to Find It:
The Offer has not yet commenced, and this communication is not a recommendation, an offer to purchase or a solicitation of an offer to sell any
shares of the Common Stock or any other securities. On the commencement date of the Offer, a tender offer statement on Schedule TO, including an offer to purchase, a letter of transmittal and related documents, will be filed with the U.S. Securities
and Exchange Commission (“SEC”) by GISI and Merger Sub, and a Solicitation/Recommendation Statement on Schedule 14D-9 will be filed with the SEC by Hill. The offer to purchase shares of Common
Stock will only be made pursuant to the offer to purchase, the letter of transmittal and related documents filed as a part of the Schedule TO. INVESTORS AND SECURITY HOLDERS ARE URGED TO READ BOTH THE TENDER OFFER STATEMENT AND THE
SOLICITATION/RECOMMENDATION STATEMENT REGARDING THE OFFER, AS THEY MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME, WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT INVESTORS AND SECURITY HOLDERS SHOULD CONSIDER
BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR COMMON STOCK, INCLUDING THE TERMS AND CONDITIONS OF THE OFFER. Investors and security holders may obtain a free copy of these statements (when available) and other documents filed with the SEC at
the website maintained by the SEC at www.sec.gov or by directing such requests to the Information Agent for the Offer, which will be named in the tender offer statement. Investors may also obtain, at no charge, the documents filed or furnished to
the SEC by Hill under the “Investors/SEC Filings” section of Hill’s website at www.Hillintl.com.
Cautionary Notice Regarding
Forward-Looking Statements:
This communication contains forward-looking statements. Forward-looking statements are generally
identified by the words “expects”, “anticipates”, “believes”, “intends”, “estimates”, “plans”, “will be” and similar expressions. These forward-looking statements include, without
limitation, statements related to the anticipated consummation of the merger with Hill and the timing and benefits thereof, GISI’s strategy, plans, objectives, expectations (financial or otherwise) and intentions, future financial results and
growth potential, anticipated product portfolio, development programs, patent terms and other statements that are not historical facts. These forward-looking statements are based on GISI’s and Hill’s current expectations and inherently
involve significant risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation,
risks related to GISI’s ability to complete the transaction on the proposed terms and schedule; whether the Offer conditions will be satisfied; whether sufficient stockholders of Hill tender their shares in the transaction; the outcome of legal
proceedings that may be instituted against Hill and/or others relating to the transaction; the failure (or delay) to receive the required regulatory approvals relating to the transaction; the possibility that competing offers will be made; risks
associated with mergers, such as the risk that the businesses will not be integrated successfully, that such integration may be more difficult, time-consuming or costly than expected or that the expected benefits of the transaction will not occur;
risks related to future opportunities and plans for Hill and its products, including uncertainty of the expected financial performance of Hill and its products; disruption from the proposed transaction, making it more difficult to conduct business
as usual or maintain relationships with customers, employees or suppliers; the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement, and the possibility that if GISI does not achieve
the perceived benefits of the proposed transaction as rapidly or to the extent anticipated by financial analysts or investors, as well as other risks related to Hill’s business detailed from time-to-time under the caption “Risk Factors” and elsewhere in Hill’s SEC filings and reports, including Hill’s Annual Report on Form 10-K for the year ended December 31, 2021 and
subsequent quarterly and current reports filed with the SEC. These risks and uncertainties may be amplified by the COVID-19 pandemic, which has caused significant economic uncertainty. The extent to which the COVID-19 pandemic impacts GISI’s and Hill’s businesses, operations, and financial results, including the duration and magnitude of such effects, will depend on numerous factors, which are unpredictable,
including, but not limited to, the duration and spread of the outbreak, its severity, the actions to contain the virus or treat its impact, and how quickly and to what extent normal economic and operating conditions can resume. GISI and Hill
undertake no duty or obligation to update any forward-looking statements contained in this communication as a result of new information, future events or changes in their expectations, except as required by law.