UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM U-6B-2 CERTIFICATE OF NOTIFICATION This certificate is filed by The Houston Exploration Company (the "Company"), an indirect subsidiary of KeySpan Corporation, which is a registered holding company. This certificate is notice that the above named Company has issued, renewed or guaranteed the security or securities described herein which issue, renewal or guaranty was exempted from the provisions of Section 6(a) of the Act and was neither the subject of a declaration or application on Form U-1 nor included within the exemption provided by Rule U-48. 1. Type of the security or securities. 6,200,000 shares of the Company's Common Stock, $.01 par value per share (the "Shares") 2. Issue, renewal or guaranty. Issue 3. Principal amount of each security. $297,600,000 4. Rate of interest per annum of each security. Not applicable. 5. Date of issue, renewal or guaranty of each security. June 2, 2004 6. If renewal of security, give date of original issue. Not applicable. 7. Date of maturity of each security. Not applicable. 8. Name of the person to whom each security was issued, renewed or guaranteed. Name No. of Shares ---- ------------- Lehman Brothers Inc. 1,798,745 Goldman, Sachs & Co. 1,798,745 Wachovia Capital Markets, LLC 477,370 A. G. Edwards & Sons, Inc. 268,125 Howard Weil Incorporated 268,125 KeyBanc Capital Markets, a Division of McDonald Investments Inc. 268,125 Petrie Parkman & Co., Inc. 268,125 BNP Paribas Securities Corp. 263,130 Comerica Securities, Inc. 263,160 Scotia Capital (USA) Inc. 263,160 BNY Capital Markets, Inc. 131,580 Natexis Bleichroeder Inc. 65,790 Wells Fargo Securities, LLC 65,790 9. Collateral given with each security, if any. None. 10. Consideration received for each security. $285,696,000 11. Application of proceeds of each security. The issuance of the Shares are to be used by the Company to finance its existing business. Specifically, the issuance will be used (i) to consolidate and pay down certain indebtedness of the Company; and (ii) for general corporate purposes. 12. Indicate by a check after the applicable statement below whether the issue, renewal or guaranty of each security was exempt from the provisions of Section 6(a) because of: a. the provisions contained in the first sentence of Section 6(b). ( ) b. the provisions contained in the fourth sentence of Section 6(b). ( ) c. the provisions contained in any rule of the Commission other than Rule 48.(X) 13. If the security or securities are exempt from the provisions of Section 6(a) by virtue of the first sentence of Section 6(b), give the figures which indicate that the security or securities aggregate (together with all other then outstanding notes and drafts of a maturity of nine months or less, exclusive of days of grace, as to which such company is primarily or secondarily liable) not more than five percentum of the principal amount and par value of the other securities of such company then outstanding. Not applicable. 2 14. If the security or securities are exempt from the provisions of Section 6(a) because of the fourth sentence of Section 6(b), name the security outstanding on January 1, 1935, pursuant to the terms of which the security or securities herein described have been issued. Not applicable 15. If the security or securities are exempt from the provisions of Section 6(a) because of any rule of the Commission other than Rule U-48, designate the rule under which exemption is claimed. Rule 52(b) SIGNATURES Pursuant to the requirements of the Public Utility Holding Company Act of 1935, the Company has duly caused this Certificate to be signed on its behalf by the undersigned thereunto duly authorized. THE HOUSTON EXPLORATION COMPANY By: /s/James Westmoreland ------------------------------- James Westmoreland Vice President and Chief Accounting Officer DATE: June 7, 2004 3