<PAGE>
THIS FILING LISTS SECURITIES HOLDINGS REPORTED
ON THE FORM 13F FILED ON AUGUST 14, 2000
PURSUANT TO A REQUEST FOR
CONFIDENTIAL TREATMENT AND FOR WHICH
THAT REQUEST
EXPIRED ON NOVEMBER 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: JUNE 30, 2000
Check here if Amendment [X ]; Amendment Number: 1
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 11/14/00
------------------ ------------------- --------
[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: 27
Form 13F Information Table Value Total: $483,400
(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
--------------- -------------- -------- -------- --------------------------
VALUE SHRS OR SH/ PUT/
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL
-------------- -------------- ----- -------- ------- --- ----
<S> <C> <C> <C> <C> <C>
ACTIVE SOFTWARE COMMON 00504E100 18,513 238,300 SH
BEST FOODS COMMON 08658U101 96,431 1,392,500 SH
BEST FOODS COMMON 08658U101 3,463 50,000 SH CALL
BURR BROWN GROUP COMMON 122574106 22,651 261,300 SH
CMP GROUP COMMON 125887109 11,757 401,100 SH
COLUMBIA ENERGY COMMON 197648108 51,509 784,900 SH
CONSOLIDATED PAPERS COMMON 209759109 13,696 374,600 SH
E TOWN CORP COMMON 269242103 751 11,300 SH
EASTERN ENTERPRISES COMMON 27637F100 1,285 20,400 SH
GEON COMPANY COMMON 37246W105 463 25,000 SH
INT'L HOME FOODS COMMON 459655106 6,679 319,000 SH
LILLY INDUSTRIES COMMON 532491107 1,503 50,000 SH
LYCOS, INC. COMMON 550818108 10,265 190,100 SH
MEDICAL MANAGER COMMON 58461C103 1,363 40,000 SH
<CAPTION>
COLUMN 1 COLUMN 6 COLUMN 7 COLUMN 8
--------------- ---------- -------- -------------------------
INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER DISCRETION MANAGERS SOLE SHARED NONE
-------------- ---------- -------- ---- ------ ----
<S> <C> <C> <C>
ACTIVE SOFTWARE SOLE SOLE
BEST FOODS SOLE SOLE
BEST FOODS SOLE NONE
BURR BROWN GROUP SOLE SOLE
CMP GROUP SOLE SOLE
COLUMBIA ENERGY SOLE SOLE
CONSOLIDATED PAPERS SOLE SOLE
E TOWN CORP SOLE SOLE
EASTERN ENTERPRISES SOLE SOLE
GEON COMPANY SOLE SOLE
INT'L HOME FOODS SOLE SOLE
LILLY INDUSTRIES SOLE SOLE
LYCOS, INC. SOLE SOLE
MEDICAL MANAGER SOLE SOLE
</TABLE>
<PAGE>
FORM 13F INFORMATION TABLE
<TABLE>
<CAPTION>
COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5
--------------- -------------- -------- -------- --------------------------
VALUE SHRS OR SH/ PUT/
NAME OF ISSUER TITLE OF CLASS CUSIP (x$1000) PRN AMT PRN CALL
-------------- -------------- ----- -------- ------- --- ----
<S> <C> <C> <C> <C> <C>
PIONEER GROUP COMMON 723684106 21,340 503,600 SH
RELIASTAR FIN. CORP. COMMON 75952U103 26,953 514,000 SH
SMITHKLINE BEECHAM COMMON 832378301 5,867 90,000 SH
SNYDER
COMMUNICATIONS COMMON 832914105 48,574 2,045,200 SH
TELEGLOBE, INC. COMMON 87941V100 11,838 560,000 SH
TERRA NETWORKS COMMON 88100W103 365 10,000 SH
VASTAR COMMON 922380100 2,464 30,000 SH
VERIO, INC. COMMON 923433106 77,845 1,403,000 SH
WEBMETHODS COMMON 94768C108 4,716 30,000 SH
WESLEY JESSEN
VISIONCARE COMMON 951018100 1,863 50,000 SH
WPP GROUP COMMON 929309300 1,198 16,500 SH
YOUNG & RUBICAM COMMON 987425105 36,617 640,300 SH
YOUNG & RUBICAM COMMON 987425105 3,431 60,000 SH CALL
<CAPTION>
COLUMN 1 COLUMN 6 COLUMN 7 COLUMN 8
--------------- ---------- -------- -------------------------
INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER DISCRETION MANAGERS SOLE SHARED NONE
-------------- ---------- -------- ---- ------ ----
<S> <C> <C>
PIONEER GROUP SOLE SOLE
RELIASTAR FIN. CORP. SOLE SOLE
SMITHKLINE BEECHAM SOLE SOLE
SNYDER
COMMUNICATIONS SOLE SOLE
TELEGLOBE, INC. SOLE SOLE
TERRA NETWORKS SOLE SOLE
VASTAR SOLE SOLE
VERIO, INC. SOLE SOLE
WEBMETHODS SOLE SOLE
WESLEY JESSEN
VISIONCARE SOLE SOLE
WPP GROUP SOLE SOLE
YOUNG & RUBICAM SOLE SOLE
YOUNG & RUBICAM SOLE NONE
</TABLE>
