Filing of Certain Prospectuses and Communications in Connection With Business Combination Transactions (425)

Filed by: Impax Laboratories, Inc. 
Pursuant to Rule 425 under the Securities Act of 1933 
and deemed filed pursuant to Rule 14a-12 
of the Securities Exchange Act of 1934 
Subject Company: Impax Laboratories, Inc. 
Commission File No.: 001-34263

This filing relates to the proposed transaction between Impax Laboratories, Inc. (“Impax”) and Amneal Pharmaceuticals LLC (“Amneal”) pursuant to the Business Combination Agreement dated as of October 17, 2017 by and among Impax, Amneal, Atlas Holdings, Inc. and K2 Merger Sub Corporation, as amended by Amendment No. 1, dated November 21, 2017, and Amendment No. 2, dated December 16, 2017.

The following is a copy of an e-mail communication distributed to Impax employees on March 15, 2018.

Update on L2 Leadership Identification Process and Next Steps

It has been a few weeks since the announcement of the proposed senior leadership team reporting to Rob Stewart in the combined company. Over these weeks, Rob has met with these leaders to discuss his high-level vision and strategy for the new Amneal post-close.

With this information, the senior leaders began the process of designing their functional organizations – aligned to the strengthened capabilities, talents and goals of the combined company.

At the same time, Rob has also been working to finalize leadership selections for both the Tech Ops and Corporate Development functions. We are making good progress in both areas and expect to communicate more details shortly.

Naming the L2 Leadership Team

Conversations continue to take place between the senior leaders and the current functional leaders across Amneal and Impax. The goal is to identify the next level functional leaders for the combined company, ensuring the new Amneal represents the best talent from both organizations.

As you might expect, due to the complexity of some of the functions, this process is moving forward at varying rates. Several senior leaders have submitted their proposed L2 functional leadership structures for review while others continue their thoughtful discussions.

Rob is reviewing the submitted proposals with Human Resources. We will begin to communicate some of these proposed L2 leaders by function as they are approved.

Next Steps

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We continue to work toward closing and are currently on track to complete the transaction in the second quarter of 2018.

Across both companies, integration planning teams have been making considerable progress identifying the top-level priorities and plans for Day 1 as a combined company. These top-level priorities and plans are focused on maintaining business continuity at close while also minimizing disruption to employees, customers, patients and other key stakeholders.

We will continue to keep you updated on the progress of the transaction and our plans to ensure a successful Day 1 as a combined company.

Additional Information and Where to Find It

This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval. This communication may be deemed to be solicitation material in respect of the proposed transaction between Impax Laboratories, Inc. (“Impax”) and Amneal Pharmaceuticals LLC (“Amneal”) pursuant to the Business Combination Agreement dated as of October 17, 2017 by and among Impax, Amneal, Atlas Holdings, Inc. (“Holdco”), and K2 Merger Sub Corporation, as amended by Amendment No. 1, dated November 21, 2017, and Amendment No. 2, dated December 16, 2017. In connection with the proposed transaction, Holdco filed a registration statement on Form S- 4, containing a proxy statement/prospectus, with the Securities and Exchange Commission (“SEC”) on November 21, 2017, Amendment No. 1 to the registration statement filed on December 29, 2017, Amendment No. 2 to the registration statement filed on January 23, 2018, Amendment No. 3 to the registration statement filed on February 1, 2018 and Amendment No. 4 to the registration statement filed on February 6, 2018, which was declared effective by the SEC on February 9, 2018. Impax has filed a definitive proxy statement on Schedule 14A with the SEC on February 12, 2018, and the definitive proxy statement and a form of proxy have been mailed to the shareholders of Impax on or about February 13, 2018. This communication is not a substitute for the registration statement, definitive proxy statement/prospectus or any other documents that Impax or Holdco may file or have filed with the SEC, or will send or have sent to stockholders in connection with the proposed business combination. INVESTORS AND SECURITY HOLDERS OF IMPAX ARE URGED TO READ ALL RELEVANT DOCUMENTS FILED WITH THE SEC, INCLUDING THE PROXY STATEMENT/PROSPECTUS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION.

Investors and security holders will be able to obtain copies of the registration statement, including the proxy statement/prospectus and other documents filed with the SEC (when available) free of charge at the SEC’s website, http://www.sec.gov. Copies of the documents filed with the SEC by Impax or Holdco will be available free of charge on Impax’s internet website at http://www.impaxlabs.com or by contacting Mark Donohue, Investor Relations and Corporate Communications at [phone].

Participants in Solicitation

Impax, Amneal, Holdco and their respective directors and executive officers may be deemed to be participants in the solicitation of proxies from Impax’s stockholders in respect of the proposed transaction. Information about the directors and executive officers of Impax is set forth in its proxy statement for its 2017 annual meeting of stockholders, which was filed with the SEC on April 5, 2017, and in its Annual Report on Form 10-K for the year ended December 31, 2017. Other information regarding the participants in the proxy solicitations and a description of their direct and indirect interests, by security holdings or otherwise, are contained in the proxy statement/prospectus regarding the proposed transaction and other relevant materials that have been or will be filed with the SEC when they become available. You may obtain free copies of these documents as described in the preceding paragraph. This communication is not intended to and shall not constitute an offer to sell or the solicitation of an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote of approval, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offering of securities shall

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be made except by means of a prospectus meeting the requirements of Section 10 of the Securities Act of 1933, as amended.

Forward-Looking Statements

This communication includes “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Forward-looking statements are based on our beliefs and assumptions. These forward-looking statements are identified by terms and phrases such as: anticipate, believe, intend, estimate, expect, continue, should, could, may, plan, project, predict, will, target, potential, forecast, and the negative thereof and similar expressions. Forward-looking statements by their nature address matters that are, to different degrees, uncertain, such as statements about the potential timing or consummation of the proposed transaction or the anticipated benefits thereof, including, without limitation, future financial and operating results. Impax cautions readers that these and other forward-looking statements are not guarantees of future results and are subject to risks, uncertainties and assumptions that could cause actual results to differ materially from those expressed in any forward-looking statements. Important risk factors that could cause actual results to differ materially from those indicated in any forward-looking statement include, but are not limited to: (i) the ability to obtain shareholder and regulatory approvals, or the possibility that they may delay the transaction or that such regulatory approval may result in the imposition of conditions that could cause the parties to abandon the transaction, (ii) the risk that a condition to effecting the transaction may not be satisfied; (iii) the ability of Impax and Amneal to integrate their businesses successfully and to achieve anticipated synergies, (iv) the possibility that other anticipated benefits of the proposed transaction will not be realized, including without limitation, anticipated revenues, expenses, earnings and other financial results, and growth and expansion of the new combined company’s operations, and the anticipated tax treatment, (v) potential litigation relating to the proposed transaction that could be instituted against Impax, Amneal or their respective directors, (vi) possible disruptions from the proposed transaction that could harm Impax’s and/or Amneal’s business, including current plans and operations, (vii) the ability of Impax or Amneal to retain, attract and hire key personnel, (viii) potential adverse reactions or changes to relationships with clients, employees, suppliers or other parties resulting from the announcement or completion of the transaction, (ix) potential business uncertainty, including changes to existing business relationships, during the pendency of the business combination that could affect Impax’s or Amneal’s financial performance, (x) certain restrictions during the pendency of the transaction that may impact Impax’s or Amneal’s ability to pursue certain business opportunities or strategic transactions, (xi) continued availability of capital and financing and rating agency actions, (xii) legislative, regulatory and economic developments; (xiii) unpredictability and severity of catastrophic events, including, but not limited to, acts of terrorism or outbreak of war or hostilities, as well as management’s response to any of the aforementioned factors; and (xiv) such other factors as are set forth in Impax’s periodic public filings with the SEC, including but not limited to those described under the headings “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Information” in Impax’s Form 10-K for the fiscal year ended December 31, 2016, in the Form S-4 filed by Holdco, in the definitive proxy statement on Schedule 14A filed by Impax and in Impax’s other filings made with the SEC from time to time, which are available via the SEC’s website at www.sec.gov. While the list of factors presented here is, and the list of factors to be presented in the proxy statement are, considered representative, no such list should be considered to be a complete statement of all potential risks and uncertainties. Unlisted factors may present significant additional obstacles to the realization of forward looking statements. Consequences of material differences in results as compared with those anticipated in the forward-looking statements could include, among other things, business disruption, operational problems, financial loss, legal liability to third parties and similar risks, any of which could have a material adverse effect on Impax’s or Amneal’s consolidated financial condition, results of operations, credit rating or liquidity. In light of these risks, uncertainties and assumptions, the events described in the forward-looking statements might not occur or might occur to a different extent or at a different time than Impax has described. All such factors are difficult to predict and beyond our control. All forward-looking statements included in this document are based upon information available to Impax on the date hereof, and unless legally required, Impax disclaims and does not undertake any obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

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