CJ C&J Energy Services Inc

Filed by Keane Group, Inc.

pursuant to Rule 425 under the Securities Act of 1933

and deemed filed pursuant to Rule 14a-12

under the Securities Exchange Act of 1934

Subject Company: C&J Energy Services, Inc.

Commission File No.: 001-38023

Date: June 28, 2019

Letter to Keane Employees

Keane Group, Inc.

Dear Keane Employee,

As announced on June 17, 2019, Keane and C&J Energy Services have agreed to combine in an all-stock merger of equals. This transaction will establish us as an industry-leading, diversified oilfield services provider and your hard work has been instrumental in positioning our company to take advantage of this opportunity.

Because you hold equity in Keane pursuant to the Keane Group, Inc. Equity and Incentive Award Plan (the “ Plan ”), we recognize that you may have questions regarding how your existing equity awards will be treated upon consummation of the merger (the “ Closing Date ”). As part of our commitment to keeping you updated on important aspects of this process, we wanted to answer some common questions that have been received since the announcement.

Pursuant to the terms of the merger agreement, C&J stockholders will receive Keane common stock for each share of C&J common stock owned. Following the Closing Date, Keane will continue to be the company listed with the Securities and Exchange Commission and its common stock will continue to trade on the New York Stock Exchange, albeit under a new name and ticker symbol. As a result, there will be no change for employees such as yourself who hold Keane common stock or unvested Keane equity, such as restricted stock units.

Keane will treat the consummation of the merger as a “change in control”, as that term is used in the Plan and your equity award agreements, for purposes of the Plan. We are pleased to inform you that, effective upon the Closing Date, our award agreements will be amended to provide that if you are terminated without cause within the twelve months (previously six months) following a change in control, you will become 100% vested in your unvested Keane equity upon such termination. If you remain employed with the combined company, or are terminated after the twelve-month transition period, your equity is not subject to accelerated vesting and will vest in accordance with the timing set forth in the award agreement.

As part of our commitment to offer you the most competitive compensation and benefits, we are currently conducting a review of our compensation and benefit programs along with those of C&J to ensure that our programs are harmonized. Any adjustments will be separately communicated to you.

As a reminder, we ask that you keep the terms of your equity awards strictly confidential. Should you have questions regarding your awards, the contents of this letter, or trading in Keane or C&J stock, you are able to discuss directly with the contacts listed below.

Forward-Looking Statements

This communication contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that are subject to risks and uncertainties and are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1993, as amended and Section 21E of the Securities Exchange Act of 1934, as amended. Where a forward-looking statement expresses or implies an expectation or belief as to future events or results, such expectation or belief is expressed in good faith and believed to have a reasonable basis. The words “believe” “continue,” “could,” “expect,” “anticipate,” “intends,” “estimate,” “forecast,” “project,” “should,” “may,” “will,” “would” or the negative thereof and similar expressions are intended to identify such forward-looking statements. These forward-looking statements are only predictions and involve known and unknown risks and uncertainties, many of which are beyond Keane’s and C&J’s control. Statements in this communication regarding Keane, C&J and the combined company that are forward-looking, including projections as to the anticipated benefits of the proposed transaction, the impact of the proposed transaction on Keane’s and C&J’s business and future financial and operating results, the amount and timing of synergies from the proposed transaction, and the closing date for the proposed transaction, are based on management’s estimates, assumptions and projections, and are subject to significant uncertainties and other factors, many of which are beyond Keane’s and C&J’s control. These factors and risks include, but are not limited to, (i) the competitive nature of the industry in which Keane and C&J conduct their business, including pricing pressures; (ii) the ability to meet rapid demand shifts; (iii) the impact of pipeline capacity constraints and adverse weather conditions in oil or gas producing regions; (iv) the ability to obtain or renew customer contracts and changes in customer requirements in the markets Keane and C&J serve; (v) the ability to identify, effect and integrate acquisitions, joint ventures or other transactions; (vi) the ability to protect and enforce intellectual property rights; (vii) the effect of environmental and other governmental regulations on Keane’s and C&J’s operations; (viii) the effect of a loss of, or interruption in operations of, one or more key suppliers, including resulting from product defects, recalls or suspensions; (ix) the variability of crude oil and natural gas commodity prices; (x) the market price and availability of materials or equipment; (xi) the ability to obtain permits, approvals and authorizations from governmental and third parties; (xii) Keane’s and C&J’s ability to employ a sufficient number of skilled and qualified workers to combat the operating hazards inherent in Keane’s and C&J’s industry; (xiii) fluctuations in the market price of Keane’s and C&J’s stock; (xiv) the level of, and obligations associated with, Keane’s and C&J’s indebtedness; and (xv) other risk factors and additional information. In addition, material risks that could cause actual results to differ from forward-looking statements include: the inherent uncertainty associated with financial or other projections; the prompt and effective integration of C&J’s businesses and the ability to achieve the anticipated synergies and value-creation contemplated by the proposed transaction; the risk associated with Keane’s and C&J’s ability to obtain the approval of the proposed transaction by their shareholders required to consummate the proposed transaction and the timing of the closing of the proposed transaction, including the risk that the conditions to the transaction are not satisfied on a timely basis or at all and the failure of the transaction to close for any other reason; the risk that a consent or authorization that may be required

for the proposed transaction is not obtained or is obtained subject to conditions that are not anticipated; unanticipated difficulties or expenditures relating to the transaction, the response of business partners and retention as a result of the announcement and pendency of the transaction; and the diversion of management time on transaction-related issues. For a more detailed discussion of such risks and other factors, see Keane’s and C&J’s filings with the Securities and Exchange Commission (the “SEC”), including under the heading “Risk Factors” in Item 1A of Keane’s Annual Report on Form 10-K for the fiscal year ended December 31, 2018, filed on February 27, 2019, and C&J’s Annual Report on Form 10-K for the fiscal year ended December 31, 2018, filed on February 27, 2019 and in other periodic filings, available on the SEC website or www.keanegrp.com or www.cjenergy.com. Keane and C&J assume no obligation to update any forward-looking statements or information, which speak as of their respective dates, to reflect events or circumstances after the date of this communication, or to reflect the occurrence of unanticipated events, except as may be required under applicable securities laws. Investors should not assume that any lack of update to a previously issued “forward-looking statement” constitutes a reaffirmation of that statement.

Important Additional Information Regarding the Merger of Equals Will Be Filed With the SEC

In connection with the proposed transaction, Keane intends to file with the SEC a registration statement on Form S-4 that will include a joint proxy statement of Keane and C&J that also constitutes a prospectus of Keane. Each of Keane and C&J also plan to file other relevant documents with the SEC regarding the proposed transaction. No offering of securities shall be made, except by means of a prospectus meeting the requirements of Section 10 of the U.S. Securities Act of 1933, as amended. Any definitive joint proxy statement/prospectus (if and when available) will be mailed to stockholders of Keane and C&J. INVESTORS AND STOCKHOLDERS ARE URGED TO READ THE REGISTRATION STATEMENT, JOINT PROXY STATEMENT/PROSPECTUS AND OTHER DOCUMENTS THAT MAY BE FILED WITH THE SEC CAREFULLY AND IN THEIR ENTIRETY IF AND WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION. Investors and stockholders will be able to obtain free copies of these documents (if and when available) and other documents containing important information about Keane and C&J, once such documents are filed with the SEC through the website maintained by the SEC at http://www.sec.gov. Copies of the documents filed with the SEC by Keane will be available free of charge on Keane’s website at http://www.keanegrp.com or by contacting Keane’s Investor Relations Department by email at investors@keanegrp.com or by phone at 281-929-0370.Copies of the documents filed with the SEC by C&J will be available free of charge on C&J’s website at www.cjenergy.com or by contacting C&J’s Investor Relations Department by email at investors@cjenergy.com or by phone at 713-260-9986.

Participants in the Solicitation

Keane, C&J and certain of their respective directors and executive officers may be deemed to be participants in the solicitation of proxies in respect of the proposed transaction. Information about the directors and executive officers of C&J is set forth in its proxy statement for its 2019 annual meeting of shareholders, which was filed with the SEC on April 9, 2019, and C&J’s Annual Report on Form 10-K for the fiscal year ended December 31, 2018, which was filed with the SEC on February 27, 2019. Information about the directors and executive officers of Keane is set forth in Keane’s proxy statement for its 2019 annual meeting of shareholders, which was filed with the SEC on April 1, 2019, and Keane’s Annual Report on Form 10-K for the fiscal year ended December 31, 2018, which was filed with the SEC on February 27, 2019. Other information regarding the participants in the proxy solicitations and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the joint proxy statement/prospectus and other relevant materials to be filed with the SEC regarding the proposed transaction when such materials become available. Investors should read the joint proxy statement/prospectus carefully when it becomes available before making any voting or investment decisions. You may obtain free copies of these documents from Keane or C&J using the sources indicated above.

No Offer or Solicitation

This document is not intended to and does not constitute an offer to sell or the solicitation of an offer to subscribe for or buy or an invitation to purchase or subscribe for any securities or the solicitation of any vote in any jurisdiction pursuant to the proposed transaction or otherwise, nor shall there be any sale, issuance or transfer of

securities in any jurisdiction in contravention of applicable law. Subject to certain exceptions to be approved by the relevant regulators or certain facts to be ascertained, the public offer will not be made directly or indirectly, in or into any jurisdiction where to do so would constitute a violation of the laws of such jurisdiction, or by use of the mails or by any means or instrumentality (including without limitation, facsimile transmission, telephone and the internet) of interstate or foreign commerce, or any facility of a national securities exchange, of any such jurisdiction.