Form 425
Filed by Bronco Drilling Company, 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: Allis-Chalmers Energy Inc.
Commission File No.: 001-02199
The communication filed herewith is a written communication sent by Bronco Drilling Company, Inc.
to its employees on January 24, 2008 in connection with the execution of the Agreement and Plan of
Merger, dated January 23, 2008, by and among Allis-Chalmers Energy Inc., Bronco Drilling Company,
Inc. and Elway Merger Sub, Inc.
To All of My Fellow Employees:
As you know, Bronco Drilling Company, Inc. has been the fastest growing drilling company in the
United States since becoming publicly traded in August of 2005. As we look toward the future we
want to continue to expand our scope and influence on the industry. With that in mind, I am very
happy to announce that Bronco Drilling has signed a merger agreement with Allis-Chalmers Energy,
Inc. which will combine the two companies.
Allis Chalmers Energy, Inc., a publicly-traded company (ALY) on the New York Stock Exchange, is a
Houston based multi-faceted oilfield services company. They provide services and equipment to oil
and natural gas exploration and production companies, domestically in Texas, Louisiana, New Mexico,
Colorado, Oklahoma, Mississippi, Utah, Wyoming, Arkansas, Alabama, West Virginia, offshore in the
Gulf of Mexico, and internationally primarily in Argentina and Mexico. Allis-Chalmers does not
have a drilling division in the United States, thus Bronco will become the drilling arm of the
combined companies.
I see this merger as a wonderful opportunity for Bronco employees to further their careers. I do
not believe that this merger will interfere with Bronco employees everyday responsibilities and it
is important to know that lines of reporting will remain the same as will Bronco Drillings name
and logo. Believe me when I say that the Company recognizes that its people are its greatest
assets. You are appreciated, valued and needed to continue Broncos future success.
Regards,
Frank Harrison
Chairman and Chief Executive Officer
Important Information
THIS COMMUNICATION IS NOT AN OFFER TO SELL THE SECURITIES OF ALLIS-CHALMERS ENERGY, INC. AND IT IS
NOT SOLICITING AN OFFER TO BUY THESE SECURITIES.
In connection with the proposed transaction, Allis-Chalmers and Bronco Drilling will file a joint
proxy statement/prospectus and both companies will file other relevant documents concerning the
proposed merger transaction with the Securities and Exchange Commission (the SEC). INVESTORS ARE
URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS WHEN IT BECOMES AVAILABLE, AND ANY OTHER
RELEVANT DOCUMENTS FILED WITH THE SEC, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION REGARDING
THE MERGER. Investors and security holders may obtain a free copy of the joint proxy
statement/prospectus (when available) and the other documents free of charge at the website
maintained by the SEC at www.sec.gov.
The documents filed with the SEC by Allis-Chalmers may be obtained free of charge from
Allis-Chalmers website at www.alchenergy.com or by calling Allis-Chalmers Investor Relations
department at (713) 369-0550.
The documents filed with the SEC by Bronco Drilling may be obtained free of charge from Bronco
Drillings website at www.broncodrill.com or by calling Bronco Drillings Investor Relations
department at (405) 242-4444.
Investors and security holders are urged to read the joint proxy statement/prospectus and the other
relevant materials when they become available before making any voting or investment decision with
respect to the proposed merger.
Allis-Chalmers and Bronco Drilling and their respective directors and executive officers may be
deemed to be participants in the solicitation of proxies from the respective stockholders of each
company in connection with the merger. Information about the directors and executive officers of
Allis-Chalmers and their ownership of Allis-Chalmers common stock is set forth in its proxy
statement filed with the SEC on April 30, 2007. Information about the directors and executive
officers of Bronco Drilling and their ownership of Bronco Drilling common stock is set forth in its
proxy statement filed with the SEC on April 30, 2007. Investors may obtain additional information
regarding the interests of such participants by reading the joint proxy statement/prospectus for
the merger when it becomes available.
Forward-Looking Statements
This communication contains forward-looking statements within the meaning of the Securities Act of
1933 and the Securities Exchange Act of 1934 regarding the benefits of the acquisition of Bronco
Drilling by Allis-Chalmers, including future financial and operating results, prospects for the
combined company, and the combined companys plans, objectives and intentions. Words such as
expects, anticipates, intends, plans, believes, seeks, estimates and similar expressions or
variations of such words are intended to identify forward-looking statements, but are not the
exclusive means of identifying forward-looking statements in this communication.
Although forward-looking statements in this communication reflect the good faith judgment of
management, such statements can only be based on facts and factors currently known to management.
Consequently, forward-looking statements are inherently subject to risks and uncertainties, and
actual results and outcomes may differ materially from the results and outcomes discussed in the
forward-looking statements. Factors that could cause or contribute to such differences in results
and outcomes include, but are not limited to, demand for oil and natural gas drilling services in
the areas and markets in which the companies operate, competition, obsolescence of products and
services, the ability to obtain financing to support operations, environmental and other casualty
risks, and the effect of government regulation. Further information about the risks and
uncertainties that may affect Allis-Chalmers and Bronco Drilling are set forth in their most recent
respective filings on Form 10-K (including without limitation in the Risk Factors section) and in
other SEC filings and publicly available documents. Readers are urged not to place undue reliance
on these forward-looking statements, which speak only as of the date of this communication. Bronco
Drilling does not undertake any obligation to revise or update any forward-looking statements in
order to reflect any event or circumstance that may arise after the date of this communication.