SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                   -----------

                                  SCHEDULE 13G
                                 (Rule 13d-102)

             INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
          TO RULES 13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED
                            PURSUANT TO RULE 13d-2(b)

                               (Amendment No.  )(1)


                                   USEC, Inc.
             -------------------------------------------------------
                                (Name of Issuer)


                                  Common Stock
             -------------------------------------------------------
                         (Title of Class of Securities)


                                    90333E108
             -------------------------------------------------------
                                 (CUSIP Number)


                                December 31, 1998
             -------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:

               [X]  Rule 13d-1(b)
               [ ]  Rule 13d-1(c)
               [ ]  Rule 13d-1(d)


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

     (1) The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which would
alter disclosures provided in a prior cover page.

     The information required on the remainder of this cover page shall not be
deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).


                               Pages 1 of 10 Pages

- ---------------------------------- --------------------------- | CUSIP NO. 90333E108 | 13G | Page 2 of 10 Pages | | ----------- | | --- --- | - ---------------------------------- --------------------------- |--------|---------------------------------------------------------------------| | 1 | NAME OF REPORTING PERSON | | | S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON | | | | | | President and Fellows of Harvard College | |--------|---------------------------------------------------------------------| | 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [X] | | | (b) [ ] | | | | |--------|---------------------------------------------------------------------| | 3 | SEC USE ONLY | | | | |--------|---------------------------------------------------------------------| | 4 | CITIZENSHIP OR PLACE OF ORGANIZATION | | | | | | Massachusetts | |-----------------|--------|---------------------------------------------------| | | 5 | SOLE VOTING POWER | | | | 9,627,900 shares | | NUMBER OF |--------|---------------------------------------------------| | SHARES | 6 | SHARED VOTING POWER | | BENEFICIALLY | | ---- | | OWNED BY |--------|---------------------------------------------------| | EACH | 7 | SOLE DISPOSITIVE POWER | | REPORTING | | 9,627,900 shares | | PERSON |--------|---------------------------------------------------| | WITH | 8 | SHARED DISPOSITIVE POWER | | | | ---- | |------------------------------------------------------------------------------| | 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON | | | | | | 9,627,900 shares | |--------|---------------------------------------------------------------------| | 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN [ ] | | | SHARES* | | | | |--------|---------------------------------------------------------------------| | 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) | | | 9.6% | |--------|---------------------------------------------------------------------| | 12 | TYPE OF REPORTING PERSON* | | | EP | - -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! Page 2 of 10 Pages

- ---------------------------------- --------------------------- | CUSIP NO. 90333E108 | 13G | Page 3 of 10 Pages | | ----------- | | --- --- | - ---------------------------------- --------------------------- |--------|---------------------------------------------------------------------| | 1 | NAME OF REPORTING PERSON | | | S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON | | | | | | John Stevens Trust | |--------|---------------------------------------------------------------------| | 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [X] | | | (b) [ ] | | | | |--------|---------------------------------------------------------------------| | 3 | SEC USE ONLY | | | | |--------|---------------------------------------------------------------------| | 4 | CITIZENSHIP OR PLACE OF ORGANIZATION | | | | | | Massachusetts | |-----------------|--------|---------------------------------------------------| | | 5 | SOLE VOTING POWER | | | | 3,300 shares | | NUMBER OF |--------|---------------------------------------------------| | SHARES | 6 | SHARED VOTING POWER | | BENEFICIALLY | | ---- | | OWNED BY |--------|---------------------------------------------------| | EACH | 7 | SOLE DISPOSITIVE POWER | | REPORTING | | 3,300 shares | | PERSON |--------|---------------------------------------------------| | WITH | 8 | SHARED DISPOSITIVE POWER | | | | ---- | |------------------------------------------------------------------------------| | 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON | | | | | | 3,300 shares | |--------|---------------------------------------------------------------------| | 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN [ ] | | | SHARES* | | | | |--------|---------------------------------------------------------------------| | 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) | | | 0.0% | |--------|---------------------------------------------------------------------| | 12 | TYPE OF REPORTING PERSON* | | | EP | - -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! Page 3 of 10 Pages

- ---------------------------------- --------------------------- | CUSIP NO. 90333E108 | 13G | Page 4 of 10 Pages | | ----------- | | --- --- | - ---------------------------------- --------------------------- |--------|---------------------------------------------------------------------| | 1 | NAME OF REPORTING PERSON | | | S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON | | | | | | Nancy Stevens Trust | |--------|---------------------------------------------------------------------| | 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [X] | | | (b) [ ] | | | | |--------|---------------------------------------------------------------------| | 3 | SEC USE ONLY | | | | |--------|---------------------------------------------------------------------| | 4 | CITIZENSHIP OR PLACE OF ORGANIZATION | | | | | | Massachusetts | |-----------------|--------|---------------------------------------------------| | | 5 | SOLE VOTING POWER | | | | 5,800 shares | | NUMBER OF |--------|---------------------------------------------------| | SHARES | 6 | SHARED VOTING POWER | | BENEFICIALLY | | ---- | | OWNED BY |--------|---------------------------------------------------| | EACH | 7 | SOLE DISPOSITIVE POWER | | REPORTING | | 5,800 shares | | PERSON |--------|---------------------------------------------------| | WITH | 8 | SHARED DISPOSITIVE POWER | | | | ---- | |------------------------------------------------------------------------------| | 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON | | | | | | 5,800 shares | |--------|---------------------------------------------------------------------| | 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN [ ] | | | SHARES* | | | | |--------|---------------------------------------------------------------------| | 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) | | | 0.0% | |--------|---------------------------------------------------------------------| | 12 | TYPE OF REPORTING PERSON* | | | EP | - -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! Page 4 of 10 Pages

- ---------------------------------- --------------------------- | CUSIP NO. 90333E108 | 13G | Page 5 of 10 Pages | | ----------- | | --- --- | - ---------------------------------- --------------------------- |--------|---------------------------------------------------------------------| | 1 | NAME OF REPORTING PERSON | | | S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON | | | | | | Harvard College Trust | |--------|---------------------------------------------------------------------| | 2 | CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [X] | | | (b) [ ] | | | | |--------|---------------------------------------------------------------------| | 3 | SEC USE ONLY | | | | |--------|---------------------------------------------------------------------| | 4 | CITIZENSHIP OR PLACE OF ORGANIZATION | | | | | | Massachusetts | |-----------------|--------|---------------------------------------------------| | | 5 | SOLE VOTING POWER | | | | 13,300 shares | | NUMBER OF |--------|---------------------------------------------------| | SHARES | 6 | SHARED VOTING POWER | | BENEFICIALLY | | ---- | | OWNED BY |--------|---------------------------------------------------| | EACH | 7 | SOLE DISPOSITIVE POWER | | REPORTING | | 13,300 shares | | PERSON |--------|---------------------------------------------------| | WITH | 8 | SHARED DISPOSITIVE POWER | | | | ---- | |------------------------------------------------------------------------------| | 9 | AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON | | | | | | 13,300 shares | |--------|---------------------------------------------------------------------| | 10 | CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN [ ] | | | SHARES* | | | | |--------|---------------------------------------------------------------------| | 11 | PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) | | | 0.0% | |--------|---------------------------------------------------------------------| | 12 | TYPE OF REPORTING PERSON* | | | EP | - -------------------------------------------------------------------------------- *SEE INSTRUCTIONS BEFORE FILLING OUT! Page 5 of 10 Pages

SCHEDULE 13G ------------ Item 1(a) Name of Issuer: USEC, Inc. 1(b) Address of Issuer's Principal Executive Offices: 2 Democracy Center 6903 Rockledge Drive Bethesda, MD 20817 Item 2(a) Name of Person Filing: (i) President and Fellows of Harvard College ("P&F") (ii) John Stevens Trust ("JST") (iii) Nancy Stevens Trust ("NST") (iv) Harvard College Trust ("HCT") 2(b) Address of Principal Business Office or, if none, Residence: (i) P&F: c/o Harvard Management Company, Inc. 600 Atlantic Avenue Boston, MA 02210 (ii) JST: c/o Harvard Management Company, Inc. 600 Atlantic Avenue Boston, MA 02210 (iii) NST: c/o Harvard Management Company, Inc. 600 Atlantic Avenue Boston, MA 02210 (iv) HCT: c/o Harvard Management Company, Inc. 600 Atlantic Avenue Boston, MA 02210 2(c) Citizenship: (i) P&F: Massachusetts (ii) JST: Massachusetts (iii) NST: Massachusetts (iv) HCT: Massachusetts 2(d) Title of Class of Securities: Common Stock 2(e) CUSIP Number: 90333E108 Item 3 The entities filing are a Group, in accordance with Rule 13d-1(b)(1)(ii)(J). Page 6 of 10 Pages

Item 4 Ownership: 4(a) Amount beneficially owned: (i) P&F: 9,627,900 shares (ii) JST: 3,300 shares (iii) NST: 5,800 shares (iv) HCT: 13,300 shares 4(b) Percent of Class: (i) P&F: 9.6% (ii) JST: 0.0% (iii) NST: 0.0% (iv) HCT: 0.0% 4(c) Number of shares as to which such person has: (i) sole power to vote or to direct the vote: (i) P&F: 9,627,900 shares (ii) JST: 3,300 shares (iii) NST: 5,800 shares (iv) HCT: 13,300 shares (ii) shared power to vote or to direct the vote: --------- (iii) sole power to dispose or to direct the disposition of: (i) P&F: 9,627,900 shares (ii) JST: 3,300 shares (iii) NST: 5,800 shares (iv) HCT: 13,300 shares (iv) shared power to dispose or to direct the disposition of: -------- Item 5 Ownership of Five Percent or Less of a Class: Not Applicable. Item 6 Ownership of More than Five Percent on Behalf of Another Person: Not Applicable. Item 7 Identification and Classification of the Subsidiary which Acquired the Security Being Reported on by the Parent Holding Company: Not Applicable. Page 7 of 10 Pages

Item 8 Identification and Classification of Members of the Group: See Exhibit A. Item 9 Notice of Dissolution of Group: Not Applicable. Item 10 Certification: By signing below the undersigned certifies that, to the best of its knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. Page 8 of 10 Pages

After reasonable inquiry and to the best of its knowledge and belief, the undersigned certifies that the information set forth in this statement is true, complete and correct. PRESIDENT AND FELLOWS OF HARVARD COLLEGE By: /s/ Michael S. Pradko --------------------------- Name: Michael S. Pradko Title: Authorized Signatory JOHN STEVENS TRUST By: /s/ Michael S. Pradko --------------------------- Name: Michael S. Pradko Title: Authorized Signatory NANCY STEVENS TRUST By: /s/ Michael S. Pradko --------------------------- Name: Michael S. Pradko Title: Authorized Signatory HARVARD COLLEGE TRUST By: /s/ Michael S. Pradko --------------------------- Name: Michael S. Pradko Title: Authorized Signatory February 12, 1999 Page 9 of 10 Pages

Exhibit A --------- Members of Group Item 3 Classification ---------------- --------------------- (1) President and Fellows of Harvard College EP (2) John Stevens Trust EP (3) Nancy Stevens Trust EP (4) Harvard College Trust EP Page 10 of 10 Pages