<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: SEPTEMBER 30, 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: 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).)
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FORM 13F SUMMARY PAGE
Report Summary:
Number of Other Included Managers: 0
Form 13F Information Table Entry Total: 62
Form 13F Information Table Value Total: $860,653
(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>
3 COM COMMON 885535104 5,407 281,800 SH
ABBOTT LAB COMMON 002824100 2,029 42,660 SH
ALCATEL ASTHOM COMMON 013904305 19,016 302,446 SH
ALCOA INC. COMMON 013817101 11,057 436,804 SH
ALTEON WEBSYSTEMS COMMON 02145A109 19,554 180,400 SH
APPLIED MATERIALS COMMON 038222105 6,213 105,198 SH
BESTFOODS COMMON 08658U101 149,028 2,048,500 SH
BP AMOCO COMMON 055622104 16,276 307,100 SH
BUSH BOAKE ALLEN COMMON 123162109 13,172 275,500 SH
CAREMARK RX, INC. COMMON 141705103 71,134 6,323,000 SH
CATALYTICA COMMON 148885106 1,238 100,000 SH
CIRCLE INT'L COMMON 172574105 2,263 74,500 SH
CLEAR CHANNEL COMMON 184502102 697 12,308 SH
CLEARNET COMMUN COMMON 184902104 13,422 302,900 SH
CMGI, INC. COMMON 125750109 732 26,200 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>
3 COM SOLE SOLE
ABBOTT LAB SOLE SOLE
ALCATEL ASTHOM SOLE SOLE
ALCOA INC. SOLE SOLE
ALTEON WEBSYSTEMS SOLE SOLE
APPLIED MATERIALS SOLE SOLE
BESTFOODS SOLE SOLE
BP AMOCO SOLE SOLE
BUSH BOAKE ALLEN SOLE SOLE
CAREMARK RX, INC. SOLE SOLE
CATALYTICA SOLE SOLE
CIRCLE INT'L SOLE SOLE
CLEAR CHANNEL SOLE SOLE
CLEARNET COMMUN SOLE SOLE
CMGI, INC. 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>
COLUMBIA ENERGY COMMON 197648108 37,247 524,600 SH
COMMERCE ONE COMMON 200693109 6,010 76,200 SH
COMPUTER SCIENCES COMMON 205363104 2,246 30,248 SH
CONAGRA COMMON 205887102 570 28,400 SH
CORNING GLASS COMMON 219350105 17,803 59,994 SH
DEXTER CORP COMMON 252165105 18,701 252,400 SH
DONALDSON LUFKIN COMMON 257661108 72,534 811,000 SH
EASTERN ENTERPRISES COMMON 27637F100 1,640 25,700 SH
EL PASO ENERGY COMMON 283905107 3,032 49,200 SH
EXXON MOBIL CORP. COMMON 30231G102 3,850 43,200 SH
FLEET FIN. WARRANTS COMMON 338915119 2,406 68,992 SH
FLEXTRONICS INT'L COMMON Y2573F102 8,369 101,905 SH
GETTHERE INC. COMMON 374266104 3,893 220,100 SH
GO2NET COMMON 383486107 3,527 65,000 SH
HAVAS COMMON 419313101 20,171 1,379,226 SH
HEALTHSOUTH COMMON 421924101 1,420 174,800 SH
ILLINOIS TOOLWORKS COMMON 452308109 2,221 39,758 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>
COLUMBIA ENERGY SOLE SOLE
COMMERCE ONE SOLE SOLE
COMPUTER SCIENCES SOLE SOLE
CONAGRA SOLE SOLE
CORNING GLASS SOLE SOLE
DEXTER CORP SOLE SOLE
DONALDSON LUFKIN SOLE SOLE
EASTERN ENTERPRISES SOLE SOLE
EL PASO ENERGY SOLE SOLE
EXXON MOBIL CORP. SOLE SOLE
FLEET FIN. WARRANTS SOLE SOLE
FLEXTRONICS INT'L SOLE SOLE
GETTHERE INC. SOLE SOLE
GO2NET SOLE SOLE
HAVAS SOLE SOLE
HEALTHSOUTH SOLE SOLE
ILLINOIS TOOLWORKS 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>
IMAX CORP COMMON 45245E109 501 29,600 SH
J.C. PENNEY COMMON 708160106 2,109 178,500 SH
JDS UNIPHASE COMMON 46612J101 26,994 285,082 SH
LYCOS COMMON 550818108 5,508 80,100 SH
LYCOS COMMON 550818108 3,782 55,000 SH CALL
MEDIMMUNE, INC. COMMON 584699102 2,873 37,665 SH
MICROSOFT, INC. COMMON 594918104 10,628 176,850 SH
MOTOROLA COMMON 620076109 9,012 319,018 SH
MMC NETWORKS COMMON 55308N102 55,521 438,900 SH
NEXTLINK COMMU. COMMON 65333H707 14,920 424,000 SH
NISOURCE COMMON 65473P105 11,617 476,600 SH
NOGATECH COMMON 62952P102 186 21,900 SH
NORTHERN TELECOM COMMON 656569100 23,449 393,688 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>
IMAX CORP SOLE SOLE
J.C. PENNEY SOLE SOLE
JDS UNIPHASE SOLE SOLE
LYCOS SOLE SOLE
LYCOS SOLE NONE
MEDIMMUNE, INC. SOLE SOLE
MICROSOFT, INC. SOLE SOLE
MOTOROLA SOLE SOLE
MMC NETWORKS SOLE SOLE
NEXTLINK COMMU. SOLE SOLE
NISOURCE SOLE SOLE
NOGATECH SOLE SOLE
NORTHERN TELECOM 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>
OPENTV CORP. COMMON G67543101 1,842 58,712 SH
PAINE WEBBER COMMON 695629105 20,438 300,000 SH
PHARMACIA CORP. COMMON 716941109 16,942 281,483 SH
PFIZER INC. COMMON 717081103 22,708 505,325 SH
PSINET INC. COMMON 74437C101 470 50,300 SH
RIO ALGOM LTD COMMON 766889109 2,957 156,000 SH
SHIRE PHARMACEUTICALS COMMON 82481R106 2,024 39,197 SH
SMITHKLINE BEECHAM COMMON 832378301 6,176 90,000 SH
SOLECTRON CORP. COMMON 834182107 2,274 49,306 SH
SPRINT COMMON 852061100 2,931 100,000 SH CALL
TELEGLOBE, INC. COMMON 87941V100 11,788 560,000 SH
TEXAS INSTRUMENTS COMMON 882508104 8,489 179,890 SH
THERMADYNE HOLDINGS COMMON 883435208 299 26,004 SH
URBAN SHOPPING CTR. COMMON 917066105 1,425 30,000 SH
WEBMETHODS COMMON 94768C108 7,386 63,898 SH
WESLEY JESSEN COMMON 951018100 8,272 215,200 SH
YOUNG & RUBICAM COMMON 987425105 40,244 813,000 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>
OPENTV CORP. SOLE SOLE
PAINE WEBBER SOLE SOLE
PHARMACIA CORP. SOLE SOLE
PFIZER INC. SOLE SOLE
PSINET INC. SOLE SOLE
RIO ALGOM LTD SOLE SOLE
SHIRE PHARMACEUTICA SOLE SOLE
SMITHKLINE BEECHAM SOLE SOLE
SOLECTRON CORP. SOLE SOLE
SPRINT SOLE NONE
TELEGLOBE, INC. SOLE SOLE
TEXAS INSTRUMENTS SOLE SOLE
THERMADYNE HOLDINGS SOLE SOLE
URBAN SHOPPING CTR. SOLE SOLE
WEBMETHODS SOLE SOLE
WESLEY JESSEN SOLE SOLE
YOUNG & RUBICAM SOLE SOLE
</TABLE>
