EXHIBIT 10(F)

                   USX CORPORATION SUPPLEMENTAL THRIFT PROGRAM

                             Effective April 1, 1983
                           As amended January 1, 2000

1.  PURPOSE
The purpose of this program is to compensate individuals for the loss of Company
matching contributions under the USX Corporation Savings Fund Plan for Salaried
Employees ("Savings Plan") that occurs due to certain limits established under
the Internal Revenue Code ("Code") or that are required under the Code.  The
term "Corporation" shall mean USX Corporation and any other company that is a
participating employer in the Savings Plan.

2.  ELIGIBILITY
Except as otherwise provided herein, an individual is a "Member" of the USX
Corporation Supplemental Thrift Program (the "Program") if he or she is an
employee of the Corporation who is eligible to participate in the Savings Plan
and either (a) is a member of the Executive Management Group, or (b) is not
permitted to make contributions to the Savings Plan at least equal to the
maximum rate of matching Company contributions applicable to his service because
of the limitations of the Code.

3.  AMOUNT OF BENEFITS
With respect to a month in which a Member's (a) ability to save on both a pre-
tax and after-tax basis under the Savings Plan at a rate at least equal to the
maximum rate of matching Company contributions applicable to his service is
restricted by law (including the limitations under Code sections 401(a)(17),
401(k), 402(g), and 415), or (b) ability to save on an after-tax basis under the
Savings Plan at a rate at least equal to the maximum rate of matching Company
contributions applicable to his service is restricted by Code section 401(m),
the full matching Company contributions which would otherwise have been
deposited into the Savings Plan on behalf of the Member will be credited for
such month to the Member's account under the Program (regardless of the Member's
rate of savings under the Savings Plan).

The amount credited to a Member's account in the Program (book entry only) will
be credited in the same manner as if the amount had been deposited in the
Savings Plan for investment in Corporation stock.  For purposes of this Program,
Corporation stock shall mean, with respect to Members who are employed in the
steel and diversified businesses of the Corporation, USX-U.S. Steel Group Common
Stock ("Steel Stock").  For all other Members, Corporation stock shall mean a
combination of USX-Marathon Group Common Stock ("Marathon Stock") and Steel
Stock having the same ratio to each other as the ratio of the Market
Capitalization of the Marathon Stock to the Market Capitalization of the Steel
Stock as of the last day of the month preceding the date on which such amounts
are credited to the Member's account.
EXHIBIT 10(F) (CONTINUED)


"Market Capitalization" shall mean, on any day, the product of the total number
of shares of Marathon Stock or Steel Stock, as the case may be, outstanding on
such day, times the closing market price on the New York Stock Exchange of a
share of Marathon Stock or Steel Stock, as the case may be, on such day.

Except as otherwise provided, the rules under the Savings Plan for eligibility,
Corporation stock values, share determination, beneficiary designation, and
vesting will be applicable under this Program.

4.   FORM OF BENEFIT
A Member shall receive a lump sum distribution of the benefits payable under
this Program upon the Member's (a) termination of employment with five or more
years of continuous service, (b) termination of employment prior to attaining
five years of continuous service with the consent of the Corporation, or (c)
pre-retirement death.  Benefits provided by this Program shall be paid by the
Corporation in cash out of the general assets of the Member's Employing Company.

In the event a Member dies prior to retirement (or after retirement but prior to
receiving the benefits credited to his account under the Program), the benefits
will be paid to the Member's surviving spouse (or to the Member's estate, if
there is no surviving spouse) in the form of a lump sum distribution.

5.   SUPPLEMENTAL TAX BENEFIT
The benefits payable under the Program will be increased, where applicable, by a
supplemental tax benefit for those Members who are eligible for favorable tax
treatment (5/10-year forward averaging and/or capital gain treatment) with
respect to a distribution from a tax-qualified plan, except in the case of a
Member who terminates employment prior to age 60 without the consent of the
Corporation.  The supplemental tax benefit is the amount necessary to provide
the net after-tax distribution from the Program (based on the maximum individual
tax rate in effect at the date of distribution) which would have been realized
had the value of the matching Company contributions credited to the Member's
account in the Program been included with the Member's account under the Savings
Plan and the total combined value been distributed in cash.  In determining the
supplemental tax benefit, any favorable tax treatment the Member would be
entitled to receive will be based solely on the total combined distribution from
the Savings Plan, while the effects, if any, of the additional early
distribution tax or the excise tax on excess distributions from the Savings Plan
will be disregarded.

6.   GENERAL PROVISIONS
 a.   Administration
   The Vice President-Administration, United States Steel and Carnegie Pension
   Fund, is responsible for the administration of this Program.  The
   administrator shall decide all questions arising out of and relating to the
   administration of this Program.  The decision of the administrator shall be
   final and conclusive as to all questions of interpretations and application
   of the Program.
EXHIBIT 10(F) (CONTINUED)


 b.   Amendment or Termination of Program
      ------------------------------------
   The Corporation reserves the right to make any changes in this Program or to
   terminate this Program as to any or all groups of employees covered under
   this Program, but in no event shall such amendment or termination adversely
   affect the benefits accrued hereunder prior to the effective date of such
   amendment or termination.  Any amendment to this Program which changes this
   Program (including any amendment which increases, reduces or alters the
   benefits of this Program) or any action which terminates this Program to any
   or all groups shall be made by a resolution of the USX Corporation Board of
   Directors (or any authorized committee of such Board) adopted in accordance
   with the bylaws of USX Corporation and the corporation law of the state of
   Delaware.

 c.   No Guarantee of Employment
      ---------------------------
   Neither the creation of this Program nor anything contained herein shall be
   construed as giving an individual hereunder any right to remain in the
   employ of the Corporation.

 d.   Nonalienation
      --------------
   No benefits payable under this Program shall be subject in any way to
   alienation, sale, transfer, assignment, pledge, attachment, garnishment,
   execution, or encumbrance of any kind by operation of law or otherwise.
   However, this section shall not apply to portions of benefits applied to
   satisfy (i) obligations for withholding of employment taxes, or (ii)
   obligations under a qualified domestic relations order.

 e.   No Requirement to Fund
      -----------------------
   Benefits provided by this Program shall be paid out of general assets of the
   Corporation.  No provisions in this Program, either directly or indirectly,
   shall be construed to require the Corporation to reserve, or otherwise set
   aside, funds for the payment of benefits hereunder.

 f.   Controlling Law
      ----------------
   To the extent not preempted by the laws of the United States of America, the
   laws of the Commonwealth of Pennsylvania shall be the controlling state law
   in all matters relating to this Program.

 g.   Severability
      -------------
   If any provisions of this Program shall be held illegal or invalid for any
   reason, said illegality or invalidity shall not affect the remaining parts
   of this Program, but this Program shall be construed and enforced as if such
   illegal or invalid provision had never been included herein.