EXHIBIT 99.4


                      CERTIFICATION PURSUANT TO SECTION 906
                        OF THE SARBANES-OXLEY ACT OF 2002

I, Marc D. Hamburg, Vice President and Chief Financial Officer of Berkshire
Hathaway Inc. (the "Company"), certify, pursuant to Section 906 of the
Sarbanes-Oxley Act of 2002, 18 U.S.C. Section 1350, that to the best of my
knowledge:


(1)   the Quarterly Report on Form 10-Q of the Company for the quarterly period
      ended June 30, 2002 (the "Report") fully complies with the requirements of
      Section 13(a) or 15(d) of the Securities Exchange Act of 1934 (15 U.S.C.
      78m or 78o(d)); and

(2)   the information contained in the Report fairly presents, in all material
      respects, the financial condition and results of operations of the
      Company.

Dated:  August 13, 2002



                                      /s/ Marc D. Hamburg
                                      ------------------------------------------
                                      Marc D. Hamburg
                                      Vice President and Chief Financial Officer