- --------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                             ----------------------
                                   SCHEDULE TO
            Tender Offer Statement Under Section 14(d)(1) or 13(e)(1)
                     of the Securities Exchange Act of 1934

                                (Amendment No. 8)

                                       AND

                                  SCHEDULE 13D
                    under the Securities Exchange Act of 1934

                                (Amendment No. 1)
                             ----------------------
                               PRIMARK CORPORATION
                       (Name of Subject Company (Issuer))
                             ----------------------
                         MARQUEE ACQUISITION CORPORATION
                             THE THOMSON CORPORATION
                      (Names of Filing Persons (Offerors))
                             ----------------------
                      Common Stock, No Par Value Per Share
                         (Title of Class of Securities)
                             ----------------------
                                    741903108
                      (CUSIP Number of Class of Securities)

                             Michael S. Harris, Esq.
                             The Thomson Corporation
                        Metro Center at One Station Place
                           Stamford Connecticut 06902
                            Telephone (203) 969-8700

  (Name, Address and Telephone Number of Persons Authorized to Receive Notices
                 and Communications on Behalf of filing persons)
                             ----------------------
                                    Copy to:
                             David W. Heleniak, Esq.
                               Shearman & Sterling
                              599 Lexington Avenue
                            New York, New York 10022
                                 (212) 848-4000

                            CALCULATION OF FILING FEE
================================================================================
      Transaction Valuation*                       Amount of Filing Fee**
- --------------------------------------------------------------------------------
         $913,518,708                                  $182,703.74
================================================================================

*    Estimated for purposes of calculating the amount of the filing fee only.
     Calculated by multiplying $38.00, the per share tender offer price, by
     24,039,966, the sum of the 20,308,103 currently outstanding shares of
     Common Stock sought in the Offer and the 3,731,863 shares of Common Stock
     subject to options that vested as of June 12, 2000.
**   Calculated as 1/50 of 1% of the transaction value.
[X]  Check the box if any part of the fee is offset as provided by Rule
     0-11(a)(2) and identify the filing with which the offsetting fee was
     previously paid. Identify the previous filing by registration statement
     number, or the Form or Schedule and the date of its filing.

Amount Previously Paid:   $182,703.74      Filing Party:The Thomson Corporation,
                                                        Marquee Acquisition
                                                        Corporation
Form or Registration No.: Schedule TO      Date Filed:  June 14, 2000


                                       1


[ ]  Check the box if the filing relates solely to preliminary communications
     made before the commencement of a tender offer.
Check the appropriate boxes to designate any transactions to which the statement
relates:

[X]  third-party tender offer subject to Rule 14d-1.

[ ]  issuer tender offer subject to Rule 13e-4.

[ ]  going-private transaction subject to Rule 13e-3.

[X]  amendment to Schedule 13D under Rule 13d-2.

Check the following box if the filing is a final amendment reporting the results
of the tender offer: [X]



                                       2



CUSIP No. 741903108

- --------------------------------------------------------------------------------
1        Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person

         MARQUEE ACQUISITION CORPORATION

         Tax ID Number: N.A.
- --------------------------------------------------------------------------------
2        Check the Appropriate Box if a Member of a Group

         (a)  :
         (b)  :
- --------------------------------------------------------------------------------
3        SEC Use Only

- --------------------------------------------------------------------------------
4        Source of Funds (See Instructions)

         WC
- --------------------------------------------------------------------------------
5        Check if Disclosure of Legal Proceedings is Required Pursuant to
         Items 2(d) or 2(e).  :

- --------------------------------------------------------------------------------
6        Citizenship or Place of Organization

         Michigan
- --------------------------------------------------------------------------------
                                    7    Sole Voting Power

                                         0
          NUMBER OF                 --------------------------------------------
           SHARES                   8    Shared Voting Power
        BENEFICIALLY
          OWNED BY                       19,607,413
            EACH                    --------------------------------------------
         REPORTING                  9    Sole Dispositive Power
          PERSON
           WITH                          0
                                    --------------------------------------------
                                    10   Shared Dispositive Power

                                         19,607,413
- --------------------------------------------------------------------------------
11        Aggregate Amount Beneficially Owned by Each Reporting Person

          19,607,413
- --------------------------------------------------------------------------------
12        Check if the Aggregate Amount in Row (11) Excludes Certain Shares
          (See Instructions)  :

- --------------------------------------------------------------------------------
13        Percent of Class Represented by Amount in Row (11)

          96.5%
- --------------------------------------------------------------------------------
14        Type of Reporting Person (See Instructions)

          CO
- --------------------------------------------------------------------------------


                                       3




- --------------------------------------------------------------------------------
1        Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person

         The Thomson Corporation

         Tax ID Number: 98/0176673
- --------------------------------------------------------------------------------
2        Check the Appropriate Box if a Member of a Group

         (a)  :
         (b)  :
- --------------------------------------------------------------------------------
3        SEC Use Only

- --------------------------------------------------------------------------------
4        Source of Funds (See Instructions)

         WC
- --------------------------------------------------------------------------------
5        Check if Disclosure of Legal Proceedings is Required Pursuant to
         Items 2(d) or 2(e).  :

- --------------------------------------------------------------------------------
6        Citizenship or Place of Organization

         Ontario, Canada
- --------------------------------------------------------------------------------
                                    7    Sole Voting Power

                                         0
          NUMBER OF                 --------------------------------------------
           SHARES                   8    Shared Voting Power
        BENEFICIALLY
          OWNED BY                       19,607,413
            EACH                    --------------------------------------------
         REPORTING                  9    Sole Dispositive Power
          PERSON
           WITH                          0
                                    --------------------------------------------
                                    10   Shared Dispositive Power

                                         19,607,413
- --------------------------------------------------------------------------------
11        Aggregate Amount Beneficially Owned by Each Reporting Person

          19,607,413
- --------------------------------------------------------------------------------
12        Check if the Aggregate Amount in Row (11) Excludes Certain Shares
          (See Instructions)  :

- --------------------------------------------------------------------------------
13        Percent of Class Represented by Amount in Row (11)

          96.5%
- --------------------------------------------------------------------------------
14        Type of Reporting Person (See Instructions)

          CO
- --------------------------------------------------------------------------------


                                       4


This Amendment No. 8 (the "Final Amendment") amends and supplements the Tender
Offer Statement on Schedule TO filed with the Securities and Exchange Commission
on June 14, 2000 (the "Schedule TO"), by Marquee Acquisition Corporation, a
Michigan corporation ("Purchaser") and an indirect wholly owned subsidiary of
The Thomson Corporation, a corporation organized under the laws of Ontario,
Canada ("Thomson"). The Schedule TO relates to the offer by Purchaser to
purchase all outstanding shares of Common Stock, no par value, including
associated common stock purchase rights (together, the "Shares"), of Primark
Corporation, a Michigan corporation (the "Company"), at a purchase price of
$38.00 per Share, net to each seller in cash, upon the terms and subject to the
conditions set forth in the Offer to Purchase dated June 14, 2000 (the "Offer to
Purchase") and in the related Letter of Transmittal, copies of which are filed
as Exhibits (a)(1) and (a)(2) to the Schedule TO (which, together with any
amendments or supplements thereto, collectively constitute the "Offer").
Pursuant to General Instruction H to Schedule TO, this Final Amendment satisfies
the reporting requirements of Rule 13(d) of the Act with respect to all
securities acquired by the purchaser in the Offer. Capitalized terms used and
not defined herein shall have the meanings ascribed to such terms in the Offer
to Purchase or in the Schedule TO.

Item 8.  Interest in Securities of the Subject Company.

         Item 8 of the Schedule TO is hereby amended and supplemented by the
following:

         At 5:00 p.m., Eastern Daylight Time, on Tuesday, September 12, 2000,
the Offer expired. Based on a preliminary count, approximately 19,607,413 Shares
were tendered pursuant to the Offer, of which 819,532 were tendered pursuant to
notices of guaranteed delivery. Such Shares constituted approximately 96.5% of
the outstanding shares. On September 12, 2000, effective as of 5:01 p.m. EDT,
all Shares validly tendered and not withdrawn prior to the expiration of the
Offer were accepted for payment. A copy of a press release announcing the
expiration of the Offer and the acceptance of validly tendered Shares is
attached hereto as Exhibit (a)(15), which is incorporated by reference herein.




                                       5



         After due inquiry and to the best of my knowledge and belief, I certify
that the information set forth in this statement is true, complete and correct.

Dated:  September 13, 2000

                                       MARQUEE ACQUISITION CORPORATION


                                       By:    /s/ Michael S. Harris
                                          --------------------------------------
                                          Name:   Michael S. Harris
                                          Title:  Vice President



                                       THE THOMSON CORPORATION


                                       By:    /s/ Michael S. Harris
                                          --------------------------------------
                                          Name:   Michael S. Harris
                                          Title:  Senior Vice President and
                                                  General Counsel


                                       6



                                  EXHIBIT INDEX






Exhibit No.
(a)(1)      Offer to Purchase, dated June 14, 2000.*
(a)(2)      Form of Letter of Transmittal.*
(a)(3)      Form of Notice of Guaranteed Delivery.*
(a)(4)      Form of Letter to Brokers, Dealers, Commercial Banks, Trust
            Companies and Other Nominees.*
(a)(5)      Form of Letter from Brokers, Dealers, Commercial Banks, Trust
            Companies and Nominees to Clients.*
(a)(6)      Form of Guidelines for Certification of Taxpayer Identification
            Number on Substitute Form W-9.*
(a)(7)      Summary Advertisement as published in The Wall Street Journal on
            June 14, 2000.*
(a)(8)      Joint Press Release issued by Thomson and the Company on June 5,
            2000.* (a)(9) Press Release issued by Thomson on June 22, 2000.**
(a)(10)     Joint Press Release issued by Thomson and the Company on June 28,
            2000.***
(a)(11)     Press Release issued by Thomson on July 12, 2000.****
(a)(12)     Press Release issued by Thomson on August 2, 2000.*****
(a)(13)     Press Release issued by Thomson on August 30, 2000.******
(a)(14)     Press Release issued by Thomson on September 1, 2000.*******
(a)(15)     Press Release issued by Thomson on September 13, 2000.
(b)         None.
(c)         None.
(d)(1)      Agreement and Plan of Merger, dated as of June 5, 2000, among
            Thomson, Purchaser and the Company.*
(d)(2)      Confidentiality Agreement dated April 4, 2000, between Thomson and
            the Company.*
(d)(3)      Shareholders Agreement, dated June 5, 2000, among Thomson,
            Purchaser, Joseph E. Kasputys, Stephen H. Curran and Michael R.
            Kargula.*
(d)(4)      Guarantee, dated June 5, 2000, of Thomson in favor of Joseph E.
            Kasputys.*
(d)(5)      Letter Agreement, dated June 5, 2000, between Primark Corporation
            and Stephen H. Curran.*
(d)(6)      Letter Agreement, dated June 5, 2000, between Primark Corporation
            and Michael R. Kargula.*
(d)(7)      Letter Agreement, dated June 5, 2000, between Primark Corporation
            and Joseph E. Kasputys.*
(g)         None.
(h)         None.


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


*       Incorporated by reference to Thomson's Schedule TO, filed June 14, 2000.
**      Incorporated by reference to Thomson's Schedule TO/A, filed June 23,
        2000.
***     Incorporated by reference to Thomson's Schedule TO/A, filed June 28,
        2000.
****    Incorporated by reference to Thomson's Schedule TO/A, filed July 13,
        2000.
*****   Incorporated by reference to Thomson's Schedule TO/A, filed August 2,
        2000.
******  Incorporated by reference to Thomson's Schedule TO/A, filed August 30,
        2000.
******* Incorporated by reference to Thomson's Schedule TO/A, filed September 1,
        2000.

                                       7

                                                                 Exhibit (a)(15)

The Thomson Corporation                                           [LOGO OMITTED]
Toronto Dominion Bank Tower, Suite 2706
PO Box 24, Toronto-Dominion Centre
Toronto, Ontario M5K 1A1
Tel (416) 360-8700   Fax (416) 360-8812
www.thomson.com


News Release


Investor Contact:                       Media Contact:
- ----------------                        -------------
John Kechejian                          Janey Loyd
Vice President, Investor Relations      Vice President, Corporate Communications
(203) 969-8700                          (203) 969-8700
john.kechejian@thomson.com              janey.loyd@thomson.com

                                        Jason Stewart
                                        Director, Public Relations
                                        (203) 969-8700
                                        jason.stewart@thomson.com


For Immediate Release
- --------------------------------------------------------------------------------
                        THE THOMSON CORPORATION COMPLETES
                         EQUITY TENDER OFFER FOR PRIMARK
- --------------------------------------------------------------------------------

         TORONTO, ONTARIO, September 13, 2000 -- The Thomson Corporation (TSE:
TOC) announced today that Marquee Acquisition Corporation (a wholly-owned
subsidiary of Thomson formed solely for the purpose of acquiring Primark's
shares) has completed its cash tender offer for all of the outstanding shares of
common stock of the Primark Corporation (NYSE/PCX: PMK).

         The tender offer expired, as scheduled, at 5:00 P.M. Eastern Daylight
Time (EDT) on Tuesday, September 12, 2000. Based on a preliminary count,
19,607,413 shares of Primark common stock (constituting approximately 96.5% of
the outstanding common stock) had been tendered and not withdrawn.

         As of 5:00 P.M. EDT on Tuesday, September 12, 2000, US$150 million in
the aggregate principal amount of the Primark 9 1/4% Senior Subordinated Notes
due 2008 (the "Notes") (constituting 100% of the outstanding Notes) had been
tendered and not withdrawn. The offer to acquire all of the outstanding Notes is
scheduled to expire on Wednesday, September 13, 2000 at 5:00 p.m. EDT. The total
purchase price will be US$1,114.65 per US$1,000 principal amount of Notes, which
includes a consent payment of US$10.00.

         In the proposed second step of the acquisition, Thomson plans to merge
Marquee with and into Primark. As a result, each share of Primark common stock
not previously purchased in the tender offer will be converted into the right to
receive US$38.00 per share. The proposed merger is not subject to the approval
of the remaining outstanding shareholders of Primark.

                                     -more-




2 of 2
The Thomson Corporation
Completes Tender Offer



         Primark will become part of Thomson Financial, a provider of
e-information services and integrated work solutions to the worldwide financial
community. Primark (www.primark.com), with 1999 revenues of US$495 million, is a
leading provider of financial and economic information products and solutions to
financial, corporate and government decision-makers worldwide. With this
acquisition, Thomson is taking another significant step toward strengthening its
global information offerings, in particular, the content and software
applications Thomson provides to the financial services market.

         Thomson Financial is a US$1.44 billion provider of e-information
services and integrated work solutions to the worldwide financial community.
Through the widest range of products and services in the industry, Thomson
Financial helps clients in more than 70 countries make better decisions, be more
productive and achieve superior results. For more information on Thomson
Financial visit (www.thomsonfinancial.com).

         Thomson Financial is part of The Thomson Corporation (www.thomson.com).
With 1999 revenues of US$5.8 billion, The Thomson Corporation is a leading,
global e-information and solutions company in the business and professional
marketplace. Thomson's common shares are listed on the Toronto and London Stock
Exchanges.

                                      -30-

         THIS NEWS RELEASE INCLUDES FORWARD-LOOKING STATEMENTS, WHICH ARE BASED
ON THE CORPORATION'S CURRENT EXPECTATIONS AND ASSUMPTIONS, AND ARE SUBJECT TO A
NUMBER OF RISKS AND UNCERTAINTIES THAT COULD CAUSE ACTUAL RESULTS TO MATERIALLY
DIFFER FROM THOSE ANTICIPATED. SUCH RISKS AND UNCERTAINTIES INCLUDE, AMONG
OTHERS, GENERAL BUSINESS AND ECONOMIC CONDITIONS AND COMPETITIVE ACTIONS.




                                       2