QuickLinks -- Click here to rapidly navigate through this document

SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549


FORM 10

GENERAL FORM FOR REGISTRATION OF SECURITIES
Pursuant to Section 12(b) or 12(g) of the Securities Exchange Act of 1934


CIMAREX ENERGY CO.
(Exact name of registrant as specified in its charter)

DELAWARE
(State of incorporation or other jurisdiction of incorporation or organization)
  45-0466694
(IRS Employer Identification No.)

1579 East 21st Street, Tulsa, OK
(Address of Principal Executive Offices)

 

74114
(Zip Code)

(918) 742-5531
Registrant's telephone number, including area code

Securities to be registered pursuant to Section 12(b) of the Act:

Title Of Each Class
To Be So Registered

  Name Of Exchange On Which
Each Class Is To Be Registered

Common Stock, par value $.01 per share   New York Stock Exchange, Inc.

Series A Junior Participating Preferred Stock Purchase Rights

 

New York Stock Exchange, Inc.

Securities to be registered pursuant to Section 12(g) of the Act:

None
(TITLE OF CLASS)





CIMAREX ENERGY CO.

I. INFORMATION INCLUDED IN INFORMATION STATEMENT AND INCORPORATED IN REGISTRATION STATEMENT ON FORM 10 BY REFERENCE

        CROSS-REFERENCE SHEET BETWEEN INFORMATION STATEMENT AND ITEMS OF FORM 10

        Our information statement may be found as Exhibit 99.1 to this Form 10. For your convenience, we have provided below a cross-reference sheet identifying where the items required by Form 10 can be found in the information statement.

ITEM
NO.

  ITEM CAPTION
  LOCATION IN INFORMATION STATEMENT
1   Business   "Summary"; "Summary Selected Historical and Pro Forma Financial Data"; "Cimarex" and "Where You Can Find More Information"
2   Financial Information   "Summary Selected Historical and Pro Forma Financial Data"; "Cimarex—Management's Discussion and Analysis of Cimarex"; "Unaudited Pro Forma Combined Condensed Financial Information"; and "Cimarex Energy Co. Consolidated Financial Statements" and notes thereto
3   Properties   "Cimarex"
4   Security Ownership of Certain Beneficial Owners and Management   "Management of Cimarex—Security Ownership of Certain Beneficial Owners and Management"
5   Directors and Executive Officers   "Management of Cimarex"
6   Executive Compensation   "Management of Cimarex"
7   Certain Relationships and Related Transactions   "Ancillary Agreements—Employee Benefits Agreement"; "Management of Cimarex—Executive Compensation"; "Management of Cimarex—Employment Agreements and Change in Control Arrangements with Named Executive Officers"; "Management of Cimarex—Interests of Certain Key and Cimarex Directors and Executive Officers in the Merger"
8   Legal Proceedings   "Cimarex—Regulatory Controls"
9   Market Price of and Dividends on the Registrant's Common Equity and Related Stockholder Matters   "Summary"; "Summary Selected Historical and Pro Forma Financial Data"; "Risk Factors"; "The Merger—Listing and Trading of Cimarex Common Stock"; "Management of Cimarex—Interests of Certain Key and Cimarex Directors and Executive Officers in the Merger"; "Security Ownership of Certain Beneficial Owners and Management"
10   Recent Sales of Unregistered Securities   Not applicable.
11   Description of Registrant's Securities to be Registered   "Description of Cimarex Capital Stock"
12   Indemnification of Directors and Officers   "Management of Cimarex—Officer and Director Indemnification"; "Management of Cimarex—Interests of Certain Key and Cimarex Directors and Executive Officers in the Merger"

2


13   Financial Statements and Supplementary Data   "Summary Selected Historical and Pro Forma Financial Data"; "Cimarex—Management's Discussion and Analysis of Cimarex"; "Unaudited Pro Forma Combined Condensed Financial Information"; and "Cimarex Energy Co. Consolidated Financial Statements" and notes thereto

II. INFORMATION NOT INCLUDED IN INFORMATION STATEMENT

ITEM 10. RECENT SALES OF UNREGISTERED SECURITIES.

        We were incorporated under the laws of the State of Delaware under the name "Helmerich & Payne Exploration and Production Co." on February 14, 2002. Helmerich & Payne Exploration and Production Co. issued 100 shares of its common stock, par value $.01 per share, to Helmerich & Payne, Inc., a Delaware corporation, in consideration of a capital contribution of the aggregate par value of the shares by Helmerich & Payne, Inc. Such issuance was exempt from registration under the Securities Act of 1933, as amended, pursuant to Section 4(2) thereof because such issuance did not involve any public offering of securities. As of April 4, 2002, our name was changed to "Cimarex Energy Co."


ITEM 14. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND FINANCIAL DISCLOSURE.

        None.


ITEM 15. FINANCIAL STATEMENTS AND EXHIBITS.

        The following is a list of financial statements included in the information statement and filed as part of this Registration Statement on Form 10:

3



EXHIBIT
NUMBER

  DESCRIPTION OF EXHIBITS
  2.1     Agreement and Plan of Merger, dated as of February 23, 2002, among Helmerich & Payne, Inc., Cimarex Energy Co., Mountain Acquisition Co. and Key Production Company, Inc. (filed as Exhibit 2.1 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

  3.1  

 

Certificate of Incorporation of Cimarex Energy Co. (filed as Exhibit 3.1 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

  3.2  

 

By-laws of Cimarex Energy Co. (filed as Exhibit 3.2 to dated May 9, 2002 the Registration Statement on Form S-4 (Registration No. 333-87948) and incorporated herein by reference)

  4.1  

 

Specimen Certificate of Cimarex Energy Co. common stock (filed as Exhibit 4.1 to Amendment No. 1 to Registration Statement on Form S-4 dated July 2, 2002 (Registration No. 333-87948) and incorporated herein by reference)

  4.2  

 

Rights Agreement, dated as of February 23, 2002, by and between Cimarex Energy Co. and UMB Bank, N.A. (filed as Exhibit 4.2 to dated May 9, 2002 the Registration Statement on Form S-4 (Registration No. 333-87948) and incorporated herein by reference)

10.1  

 

Distribution Agreement, dated as of February 23, 2002, by and between Helmerich & Payne, Inc. and Cimarex Energy Co. (filed as Exhibit 10.1 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

10.2  

 

Tax Sharing Agreement, dated as of February 23, 2002, by and between Helmerich & Payne, Inc. and Cimarex Energy Co. (filed as Exhibit 10.2 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

10.3  

 

Employee Benefits Agreement, dated as of February 23, 2002, by and between Helmerich & Payne, Inc. and Cimarex Energy Co. (filed as Exhibit 10.3 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

10.4  

 

First Amendment to Employee Benefits Agreement, dated August 2, 2002, by and among Helmerich & Payne, Inc., Cimarex Energy Co. and Key Production Company, Inc. (filed as Exhibit 10.3.1 to Amendment No. 2 to the Registration Statement on Form S-4 dated August 2, 2002 (Registration No. 333-87948) and incorporated herein by reference)

10.5  

 

Employment Agreement, dated September 1, 1992, by and between F.H. Merelli and Key Production Company, Inc. (filed as Exhibit 10.5 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

 

 

 

4



10.6  

 

Employment Agreement, dated September 7, 1999, by and between Paul Korus and Key Production Company, Inc. (filed as Exhibit 10.6 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

10.7  

 

Employment Agreement, dated October 25, 1993, by and between Thomas E. Jorden and Key Production Company, Inc. (filed as Exhibit 10.7 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

10.8  

 

Employment Agreement, dated February 2, 1994, by and between Stephen P. Bell and Key Production Company, Inc. (filed as Exhibit 10.8 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

10.9  

 

Employment Agreement, dated March 11, 1994, by and between Joseph R. Albi and Key Production Company, Inc. (filed as Exhibit 10.9 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

10.10

 

Change of Control Agreement, dated April 11, 2002, by and between Steven R. Shaw and Helmerich & Payne, Inc. (filed as Exhibit 10.10 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference)

10.11

 

Key Production Company, Inc. Income Continuance Plan, dated effective June 1, 1994 (incorporated by reference to Exhibit 10.18 to Key Production Company, Inc.'s Form 10-K for the fiscal year ended December 31, 1992, file no. 0-17162)

10.12

 

Employment Agreement, dated March 20, 2002, by and between David Honeyfield and Key Production Company, Inc. (filed as Exhibit 10.12 to Amendment No. 1 to Registration Statement on Form S-4 dated July 2, 2002 (Registration No. 333-87948) and incorporated herein by reference)

21.1  

 

Subsidiaries of the Registrant (filed as Exhibit 21.1 to the Registration Statement on Form S-4 dated May 9, 2002 (Registration No. 333-87948) and incorporated herein by reference

99.1  

 

Cimarex Energy Co. Information Statement, dated September    , 2002

5



SIGNATURE

        Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: September 3, 2002   CIMAREX ENERGY CO.

 

 

By:

 

/s/  
STEVEN R. MACKEY      
       
Steven R. Mackey
Vice President and Secretary

6




QuickLinks

CIMAREX ENERGY CO.
SIGNATURE