SC TO-T/A

                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549

                                ---------------
                     AMENDMENT NO. 4 (FINAL AMENDMENT) TO
                                  SCHEDULE TO
                     TENDER OFFER STATEMENT UNDER SECTION
          14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934
                               ----------------

                          JOHNS MANVILLE CORPORATION
                      (Name of Subject Company (Issuer))

                      J ACQUISITION CORPORATION (OFFEROR)
                   BERKSHIRE HATHAWAY INC. (OFFEROR PARENT)
   (Names of Filing Persons (identifying status as offeror, issuer or other
                                   person))

                    COMMON STOCK, PAR VALUE $0.01 PER SHARE
                        (Title of Class of Securities)

                                  478129 10 9
                     (CUSIP Number of Class of Securities)

                                ---------------
                                MARC D. HAMBURG
                                VICE PRESIDENT
                            BERKSHIRE HATHAWAY INC.
                               1440 KIEWIT PLAZA
                               OMAHA, NE  68131
                           TELEPHONE: (402) 346-1400
(Name, address and telephone number of person authorized to receive notices and
                  communications on behalf of filing persons)

                                ---------------
                                   COPY TO:
                            R. GREGORY MORGAN, ESQ.
                          MUNGER, TOLLES & OLSON, LLP
                            355 SOUTH GRAND AVENUE
                            LOS ANGELES, CA  90071
                           TELEPHONE: (213) 683-9100
                                ---------------

                           CALCULATION OF FILING FEE

           TRANSACTION VALUATION*                AMOUNT OF FILING FEE
- --------------------------------------------------------------------------------

                $1,724,196,708                         $344,840

- --------------------------------------------------------------------------------

* Estimated for purposes of calculating the amount of the filing fee only.  The
amount assumes the purchase of a total of 132,630,516 shares of outstanding
common stock, par value $0.01 per share, of the Issuer ("Issuer Common Stock")
at an offer price of $13.00 per share.  The number of outstanding shares of
Issuer Common Stock has been calculated by subtracting the 4,786,900 shares of
Issuer Common Stock beneficially owned by Offer Parent from the 137,417,416
shares of Issuer Common Stock outstanding as of December 28, 2000.

[X] Check box if any part of the fee is offset as provided by Rule 0-11(a)(2)
and identify the filing with which the offsetting fee was previously paid.
Identify the previous filing by registration statement number, or the Form or
Schedule and the date of its filing.

Amount Previously Paid: $344,840
Form or Registration No.: Schedule TO
Filing Party: Berkshire Hathaway Inc. and J Acquisition Corporation
Date Filed: December 29, 2000

[ ] Check the box if the filing relates solely to preliminary communications
made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the
statement relates:

[X] third-party tender offer subject to Rule 14d-1.
[ ] issuer tender offer subject to Rule 13e-4.
[ ] going-private transaction subject to Rule 13e-3.
[ ] amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results
of the tender offer: [X]

- -------------------------------------------------------------------------------
- -------------------------------------------------------------------------------


     This Amendment No. 4, filed on February 26, 2001, supplements and amends
the Tender Offer Statement on Schedule TO filed on December 29, 2000 and amended
by Amendment No. 1 filed on January 16, 2001, Amendment No. 2 filed on
January 30, 2001 and Amendment No. 3 filed on February 15, 2001 (as amended, the
"Statement"), relating to the offer by J Acquisition Corporation, a Delaware
corporation ("Purchaser") and a wholly owned subsidiary of Berkshire Hathaway
Inc., a Delaware corporation ("Berkshire"), to purchase all of the outstanding
Common Stock, par value $0.01 per share (the "Shares"), of Johns Manville
Corporation, a Delaware corporation (the "Company"), as set forth in the
Statement. Any capitalized term not defined herein has the meaning ascribed to
such term in the Statement or in the Offer to Purchase referred to therein.

ITEM 8.  INTEREST IN SECURITIES OF THE SUBJECT COMPANY

     Item 8 is amended and supplemented by the addition of the following:

     The Offer expired at 11:59 p.m., New York City time, on Friday, February
23, 2001.  Following the expiration of the Offer, Purchaser accepted for payment
all Shares validly tendered pursuant to the Offer.  Purchaser was informed by
the Depositary that approximately 130,224,340 Shares were validly tendered and
not withdrawn as of the termination of the Offer, including 524,861 Shares
tendered by notice of guaranteed delivery.  This represented approximately 94.7%
of the issued and outstanding Shares of the Company.  In addition, Berkshire
already owned 4,788,900 Shares representing approximately 3.5% of the issued and
outstanding Shares.

     Pursuant to the Agreement and Plan of Merger, dated December 19, 2000 among
Purchaser, Berkshire and the Company, Purchaser intends to cause the Merger to
become effective as soon as practicable.  In connection with the Merger, each
Share issued and outstanding immediately prior to the Effective Time held by
stockholders (other than Parent or subsidiaries of Parent and dissenting
stockholders who have properly exercised their appraisal rights in accordance
with applicable Delaware law) will be canceled and converted automatically into
the right to receive $13.00 in cash.


ITEM 12.  EXHIBITS

     Item 12 is amended to add the following exhibit:

     (a)(11) Text of press release issued by Berkshire on February 24, 2001.


                                   SIGNATURES

     After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.


                                    J ACQUISITION CORPORATION

                                    By    /s/ Marc D. Hamburg
                                    ____________________________________
                                    Name:   Marc D. Hamburg
                                    Title:  President, Secretary and Treasurer


                                    BERKSHIRE HATHAWAY INC.

                                    By   /s/ Marc D. Hamburg
                                    ____________________________________
                                    Name:   Marc D. Hamburg
                                    Title:  Vice President and
                                            Chief Financial Officer


Dated: February 26, 2001


                                 EXHIBIT INDEX

* (a)(1) Offer to Purchase, dated December 29, 2000.

* (a)(2) Form of Letter of Transmittal.

* (a)(3) Form of Notice of Guaranteed Delivery.

* (a)(4) Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies
and Other Nominees.

* (a)(5) Form of Letter to Clients for use by Brokers, Dealers, Commercial
Banks, Trust Companies and Other Nominees.

* (a)(6) Text of joint press release issued by Berkshire and the Company dated
December 20, 2000 (incorporated by reference from the Tender Offer Statement on
Schedule TO filed by Berkshire with the Securities and Exchange Commission on
December 20, 2000).

* (a)(7) Guidelines for Certification of Taxpayer Identification Number on
Substitute Form W-9.

* (a)(8) Form of summary advertisement, dated December 29, 2000.

* (a)(9) Text of press release issued by Berkshire and the Company, dated
January 29, 2001.

* (a)(10) Text of press release issued by Berkshire, dated February 14, 2001.

  (a)(11) Text of press release issued by Berkshire, dated February 24, 2001.

* (d)(1) Agreement and Plan of Merger, dated as of December 19, 2000, among
Berkshire, Purchaser and the Company (incorporated herein by reference to
Exhibit 2.1 of the Current Report on Form 8-K filed by the Company with the
Securities and Exchange Commission on December 22, 2000).

* (d)(2) Stockholder Agreement, dated as of December 19, 2000, among Berkshire,
Purchaser and the Manville Personal Injury Settlement Trust (incorporated herein
by reference to Exhibit 2.3 of the Current Report on Form 8-K filed by the
Company with the Securities and Exchange Commission on December 22, 2000).

* (d)(3) Amended and Restated Tax Matters and Amended Trust Relationship
Agreement, dated as of December 19, 2000, by and between the Company and the
Manville Personal Injury Settlement Trust (incorporated herein by reference to
Exhibit 2.2 of the Current Report on Form 8-K filed by the Company with the
Securities and Exchange Commission on December 22, 2000).

* (d)(4) Share Purchase Agreement, dated as of December 19, 2000, by and between
the Company and the Manville Personal Injury Settlement Trust (incorporated
herein by reference to Exhibit 2.4 of the Current Report on Form 8-K filed by
the Company with the Securities and Exchange Commission on December 22, 2000).

* (d)(5) Letter Agreement, dated as of December 19, 2000, by and between the
Company and the Manville Personal Injury Settlement Trust (incorporated herein
by reference to Exhibit 4 to Amendment No. 18 to the Schedule 13D filed by the
Manville Personal Injury Settlement Trust with the Securities and Exchange
Commission on December 22, 2000).

* Previously filed

EX-99.(A)(11)

                                                                 Exhibit (a)(11)
                            BERKSHIRE HATHAWAY INC.
                                  NEWS RELEASE


FOR IMMEDIATE RELEASE                                          February 24, 2001


  BERKSHIRE HATHAWAY INC. SUBSIDIARY SUCCESSFULLY COMPLETES CASH TENDER OFFER
                    FOR SHARES OF JOHNS MANVILLE CORPORATION

Omaha, Nebraska, February 24, 2001 - Berkshire Hathaway Inc. (NYSE:  BRK.A,
BRK.B) announced today successful completion of the cash tender offer by a
subsidiary of Berkshire Hathaway for all outstanding shares of common stock of
Johns Manville Corporation (NYSE:  JM).  The tender offer expired at 11:59 p.m.,
New York City time, on Friday, February 23, 2001.  Berkshire Hathaway, through
its wholly owned subsidiary making the offer, will accept for purchase all
shares validly tendered and not withdrawn prior to the expiration of the offer.
Based on information provided by EquiServe Trust Company, N.A., as paying agent,
approximately 130.2 million shares of Johns Manville will be acquired by
Berkshire Hathaway's subsidiary out of the approximately 137.4 million shares
currently outstanding, or approximately 94.7 % of all outstanding shares.  In
addition, Berkshire already owned 4,788,900 shares, or approximately 3.5% of the
outstanding shares.  Therefore, Berkshire and its wholly owned subsidiary
together will own approximately 98.2 % of Johns Manville's outstanding shares.

Payment for shares properly tendered and accepted will be made as promptly as
practicable and, in the case of shares tendered by guaranteed delivery
procedures, promptly after timely delivery of shares and required documentation.

As previously announced, Berkshire Hathaway will acquire the remaining Johns
Manville shares in a merger in which each share of Johns Manville common stock
will be converted into the right to receive $13.00 in cash and following which
Johns Manville will become a wholly owned subsidiary of Berkshire Hathaway.
Berkshire Hathaway and Johns Manville expect to consummate the merger as soon as
practicable.

Berkshire Hathaway is a holding company owning subsidiaries engaged in a number
of diverse business activities. The most important of these is the property and
casualty insurance business conducted on both a direct and reinsurance basis
through a number of subsidiaries.

This release contains "forward-looking statements" within the meaning of the
Private Securities Litigation Reform Act of 1995.  Forward-looking statements
are based on current expectations about future events and are subject to risks,
uncertainties, and assumptions about the companies' businesses, economic and
market factors, and the industries in which the companies do business, among
other things.  Actual results could differ materially from those forecast in the
forward-looking statements as a result of, among other things, acquisitions, the
development of new products and services, the effect of competitive products and
services, and general economic conditions.


FOR FURTHER INFORMATION CONTACT:

Berkshire Hathaway Inc.
     Marc D. Hamburg -- (402) 346-1400