<PAGE>
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Form 13F
Form 13F COVER PAGE
Report for the Calendar Year or Quarter Ended: December 31, 2000
-----------------------
Check Here if Amendment / /; Amendment Number:
---------
This Amendment (Check only one.): / / is a restatement.
/ / adds new holdings entries.
Institutional Investment Manager Filing this Report:
Name: Mark S. Siegel
-------------------------------
Address: 1801 Century Park East
Suite 1111
-------------------------------
Los Angeles, CA 90067
-------------------------------
-------------------------------
Form 13F File Number: 28-4186
---------------------
The institutional investment manager filing this report and the person by
whom it is signed hereby represent that the person signing the report is
authorized to submit it, that all information contained herein is true,
correct and complete, and that it is understood that all required items,
statements, schedules, lists, and tables, are considered integral parts of
this form.
Person Signing this Report on Behalf of Reporting Manager:
Name: Mark S. Siegel
-------------------------------
Title: President
-------------------------------
Phone: (310) 843-0050
-------------------------------
Signature, Place, and Date of Signing:
/s/ MARK S. SIEGEL Los Angeles, California 1/17/2001
------------------------------- ----------------- -------------
[Signature] [City, State] [Date]
Report Type (Check only one.):
/X/ 13F HOLDINGS REPORT. (Check here if all holdings of this reporting
manager are reported in this report.)
<PAGE>
/ / 13F NOTICE. (Check here if no holdings reported are in this report,
and all holdings are reported by other reporting manager(s).)
/ / 13F COMBINATION REPORT. (Check here if a portion of the holdings for
this reporting manager are reported in this report and a portion are
reported by other reporting manager(s).)
List of Other Managers Reporting for this Manager:
[If there are no entries in this list, omit this section.]
Form 13F File Number Name
28-4186 REMY INVESTORS AND CONSULTANTS, INC.
--------------- ------------------------------------
<PAGE>
<TABLE>
<CAPTION>
FORM 13F INFORMATION TABLE
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
--------------------------------- ---------------- --------- -------- ----------------- ---------- --------- -----------------------
VALUE SHRS OR SH/ PUT/ INVSTMNT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL DSCRETN MANAGERS SOLE SHARED NONE
--------------------------------- ---------------- --------- -------- -------- --- ---- ---------- --------- -------- -------- -----
<S> <C> <C> <C> <C> <C> <C> <C> <C> <C> <C> <C>
------------------------------------------------------------------------------------------------------------------------------------
UTI ENERGY CORP. CLASS A 903387108 198,221 6,029,524 x x
COMMON
------------------------------------------------------------------------------------------------------------------------------------
VARIFLEX, INC. CLASS A 922242102 7,917 1,666,667 x x
COMMON
------------------------------------------------------------------------------------------------------------------------------------
VIACOM, INC. CLASS B 925524308 33,154 709,180 x x
COMMON
------------------------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
COLUMN TOTALS 239,291
------------------------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
</TABLE>
<PAGE>
Form 13F SUMMARY PAGE
Report Summary:
Number of Other Included Managers:
--------------------
Form 13F Information Table Entry Total:
--------------------
Form 13F Information Table Value Total: $ 239,291
--------------------
(thousands)
List of Other Included Managers:
Provide a numbered list of the name(s) and Form 13F file number(s) of all
institutional investment managers with respect to which this report is filed,
other than the manager filing this report.
NONE