<PAGE>
THIS FILING LISTS SECURITIES HOLDINGS REPORTED
ON THE FORM 13F FILED ON NOVEMBER 15, 1999
PURSUANT TO A REQUEST FOR
CONFIDENTIAL TREATMENT AND FOR WHICH
THAT REQUEST
EXPIRED ON AUGUST 14, 2000
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
Form 13F
FORM 13F COVER PAGE
Report for the Calendar Year or Quarter Ended: September 30, 1999
Check here if Amendment [ x ]; Amendment Number: 3
This Amendment (Check only one.): [ ] is a restatement.
[x] adds new holdings entries.
Institutional Investment Manager Filing this Report:
Name: Chesapeake Partners Management Co., Inc.
Address: 1829 Reisterstown Road
Suite 220
Baltimore, Maryland 21208
Form 13F File Number: 28-4120
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 D. Lerner
Title: Vice President
Phone: (410) 602-0195
Signature, Place, and Date of Signing:
/s/ Mark D. Lerner Baltimore, Maryland August 14, 2000
------------------ ------------------- ---------------
[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.)
[ ] 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).)
<PAGE>
FORM 13F SUMMARY PAGE
Report Summary:
Number of Other Included Managers: 0
-----------------------------
Form 13F Information Table Entry Total: 18
------------------------------
Form 13F Information Table Value Total: $269,289
-----------------------------
(thousands)
List of Other Included Managers:
Provide a numbered list of 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.
[If there are no entries in this list, state "NONE" and omit the column headings
and list entries.]
None
<PAGE>
FORM 13F INFORMATION TABLE
<TABLE>
<CAPTION>
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7
--------------------- -------- ---------- -------- -------------------------- ---------- --------
TITLE OF VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER
NAME OF ISSUER CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGERS
<S> <C> <C> <C> <C> <C> <C> <C> <C>
AT&T Corp Common 001957109 $4,350 100,000 SH PUT SOLE
------------------------------------------------------------------------------------------------------------------------
AT&T Corp Common 001957109 $4,350 100,000 SH CALL SOLE
------------------------------------------------------------------------------------------------------------------------
Aztec Technology Common 05480L101 $1,714 996,946 SH SOLE
------------------------------------------------------------------------------------------------------------------------
CMP Group Common 125887109 $3,906 148,100 SH SOLE
------------------------------------------------------------------------------------------------------------------------
Comsat Corp. Common 20564D107 $13,228 446,520 SH SOLE
------------------------------------------------------------------------------------------------------------------------
Foamex International Common 344123104 $2,141 305,900 SH SOLE
------------------------------------------------------------------------------------------------------------------------
GTE Corp. Common 362320103 $12,300 160,000 SH SOLE
------------------------------------------------------------------------------------------------------------------------
Hannaford Bros. Common 410550107 $37,973 539,100 SH SOLE
------------------------------------------------------------------------------------------------------------------------
IPC Communications Common 44980K206 $24,293 395,000 SH SOLE
------------------------------------------------------------------------------------------------------------------------
Media One Common 58440J104 $84,926 1,243,200 SH SOLE
------------------------------------------------------------------------------------------------------------------------
Monsanto Common 611662107 $1,784 50,000 SH CALL SOLE
------------------------------------------------------------------------------------------------------------------------
Qwest
Communications Common 749121109 $4,730 160,000 SH SOLE
------------------------------------------------------------------------------------------------------------------------
Telecom Italia Common 87927W106 $6,981 81,000 SH SOLE
------------------------------------------------------------------------------------------------------------------------
United Water Common 913190104 $653 20,000 SH SOLE
------------------------------------------------------------------------------------------------------------------------
UST Corp. Common 902900109 $787 25,600 SH SOLE
------------------------------------------------------------------------------------------------------------------------
<CAPTION>
COLUMN 1 COLUMN 8
--------------------- -----------------------------------
VOTING AUTHORITY
NAME OF ISSUER SOLE SHARED NONE
<S> C> <C> <C>
AT&T Corp N/A
-------------------------------------------------------------------------
AT&T Corp N/A
-------------------------------------------------------------------------
Aztec Technology SOLE
-------------------------------------------------------------------------
CMP Group SOLE
-------------------------------------------------------------------------
Comsat Corp. SOLE
-------------------------------------------------------------------------
Foamex International SOLE
-------------------------------------------------------------------------
GTE Corp. SOLE
-------------------------------------------------------------------------
Hannaford Bros. SOLE
-------------------------------------------------------------------------
IPC Communications SOLE
-------------------------------------------------------------------------
Media One SOLE
-------------------------------------------------------------------------
Monsanto N/A
-------------------------------------------------------------------------
Qwest
Communications SOLE
-------------------------------------------------------------------------
Telecom Italia SOLE
-------------------------------------------------------------------------
United Water SOLE
-------------------------------------------------------------------------
UST Corp. SOLE
-------------------------------------------------------------------------
</TABLE>
<PAGE>
FORM 13F INFORMATION TABLE
<TABLE>
<CAPTION>
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7
--------------------- -------- ---------- -------- ----------------------- ---------- --------
TITLE OF VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER
NAME OF ISSUER CLASS CUSIP (x$1000) PRN AMT PRN CALL DISCRETION MANAGERS
<S> <C> <C> <C> <C> <C> <C> <C> <C>
US West, Inc. Common 91273H101 $57,171 1,001,900 SH SOLE
------------------------------------------------------------------------------------------------------------------------
US West, Inc. Common 91273H101 $5,706 100,000 SH CALL SOLE
------------------------------------------------------------------------------------------------------------------------
Wicor, Inc. Common 929253102 $2,296 79,000 SH SOLE
------------------------------------------------------------------------------------------------------------------------
<CAPTION>
COLUMN 1 COLUMN 8
--------------------- -------------------------------
VOTING AUTHORITY
NAME OF ISSUER SOLE SHARED NONE
<S> <C> <C> <C>
US West, Inc. SOLE
---------------------------------------------------------------
US West, Inc. N/A
---------------------------------------------------------------
Wicor, Inc. SOLE
---------------------------------------------------------------
</TABLE>
