<PAGE>
================================================================================
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
-----------------------
SCHEDULE TO/A
(RULE 14D-100)
TENDER OFFER STATEMENT UNDER SECTION 14(D)(1) OR SECTION 13(E)(1)
OF THE SECURITIES EXCHANGE ACT OF 1934
(AMENDMENT NO. 10)
-----------------------
GENER S.A.
(Name of Subject Company (Issuer))
-----------------------
THE AES CORPORATION
MERCURY CAYMAN CO. III, LTD.
(Name of Filing Persons (Offerors))
-----------------------
AMERICAN DEPOSITARY SHARES (EACH REPRESENTING 68 SHARES
OF COMMON STOCK, NO PAR VALUE)
(Title of Class of Securities)
-----------------------
368731105
(CUSIP Number of Class of Securities)
-----------------------
BARRY J. SHARP
SENIOR VICE PRESIDENT AND CHIEF FINANCIAL OFFICER
THE AES CORPORATION
1001 NORTH 19TH STREET
ARLINGTON, VIRGINIA 22209
(703) 522-1315
(Name, Address and Telephone Number of Person
Authorized to Receive Notices and Communications on Behalf of Filing Persons)
-----------------------
Copy to:
Michael E. Gizang, Esq.
Skadden, Arps, Slate, Meagher & Flom LLP
Four Times Square
New York, New York 10036
Telephone: (212) 735-3000
-----------------------
CALCULATION OF FILING FEE
TRANSACTION VALUATION* AMOUNT OF FILING FEE**
$440,264,006.40 $90,627.00
===============================================================================
<PAGE>
--------------------------------------------------------------------------------
* Estimated for purposes of calculating the amount of the filing fee only in
accordance with Rules 0-11(d) and 0-11(a)(4) under the Securities Exchange
Act of 1934, based upon (a) $16.03125, the average of the high and low
price per Gener American Depositary Share on December 15, 2000, as reported
on the New York Stock Exchange Composite Transaction Tape, multiplied by
(b) 27,462,862, representing the aggregate number of Gener American
Depositary Shares AES estimates will be the maximum number of Gener ADSs
outstanding on the expiration date of the U.S. Offer.
** One-fiftieth of 1% of the value of the transaction.
[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: $36,327 plus $54,300 Form or Registration No.:
Registration Statement on Form S-4 and Amendment No. 4 thereto. Filing
Party: The AES Corporation Date Filed: November 9, 2000 and December 21,
2000 respectively
[ ] Check the box if the filing relates solely to preliminary communications
made before the commencement of a tender offer.
Check the appropriate boxes below 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.
[ ] 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: [ ]
This Amendment No. 10 amends and supplements the Tender Offer Statement on
Schedule TO initially filed on November 9, 2000 (the "Schedule TO") by Mercury
Cayman Co. III, Ltd., a limited company organized under the laws of the Cayman
Islands (the "Purchaser") and a wholly owned subsidiary of The AES Corporation,
a Delaware corporation ("AES"), relating to the offer by the Purchaser to
exchange each issued and outstanding American Depositary Share (each, an "ADS"
and collectively, "ADSs") of Gener S.A. ("Gener"), each representing 68 shares
of Gener common stock, no par value (the "Shares"), for a fraction of a share of
common stock, par value $ 0.01 per share, of AES (the "AES Shares"), on the
terms and subject to the conditions described in the Prospectus (as defined
below), as amended by Amendment No. 5 thereto, dated December 8, 2000 (the
"Fifth Amendment"), Amendment No. 6 thereto, dated December 13, 2000 (the "Sixth
Amendment"), Amendment No. 7 thereto, dated December 14, 2000 (the "Seventh
Amendment"), Amendment No. 8 thereto, dated December 21, 2000 (the "Eighth
Amendment"), and Amendment No. 9 thereto, dated December 22, 2000 (the "Ninth
Amendment") and the related ADS Letter of Transmittal (collectively referred to
as the "Offer").
AES initially filed a Registration Statement on Form S-4 relating to the
AES Shares to be issued to holders of Gener ADSs in the Offer on November 9,
2000, which has subsequently been amended by Amendment No. 1 thereto, dated
December 7, 2000, Amendment No. 2 thereto, dated December 13, 2000, Amendment
No. 3 thereto, dated December 14, 2000, and Amendment No. 4 thereto, dated
December 22, 2000 (the "Registration Statement"). The terms and conditions of
the Offer are set forth in the final prospectus dated December 22, 2000, which
is a part of the Registration Statement (the "Prospectus"), and the related
Letter of Transmittal, which are annexed to the Schedule TO as Exhibits (a)(18)
and (a)(2), respectively.
All of the information in the Prospectus, the Fifth Amendment, the Sixth
Amendment, the Seventh Amendment, the Eighth Amendment, the Ninth Amendment and
the related ADS Letter of Transmittal, and any prospectus supplement or other
supplement or amendment thereto related to the Offer hereafter filed with the
Securities and Exchange Commission by AES, is hereby incorporated by reference
in answer to Items 2 through 11 of this Schedule TO.
2
<PAGE>
ITEM 12. EXHIBITS.
Item 12 is hereby amended and supplemented to add the following exhibit:
<TABLE>
<S> <C>
(a)(19) Press release dated December 22, 2000.
</TABLE>
3
<PAGE>
SIGNATURE
After due inquiry and to the best of my knowledge and belief, we certify
that the information set forth in this statement is true, complete and correct.
MERCURY CAYMAN CO. III, LTD.
By: /s/ Naveed Ismail
------------------------------------
Name: Naveed Ismail
Title: President
Dated: December 26, 2000
THE AES CORPORATION
By: /s/ Paul T. Hanrahan
------------------------------------
Name: Paul T. Hanrahan
Title: Senior Vice President
Dated: December 26, 2000
4
<PAGE>
EXHIBIT INDEX
<TABLE>
<CAPTION>
EXHIBIT
NUMBER EXHIBIT NAME
--------------- ---------------------------------------------------------------------------------------
<S> <C>
(a)(1) Prospectus relating to AES Shares to be issued in the U.S. Offer (incorporated by
reference from The AES Corporation Registration Statement on Form S-4 filed on
November 9, 2000).*
(a)(2) Form of ADS Letter of Transmittal (incorporated by reference to Exhibit 99.1 to The
AES Corporation Registration Statement on Form S-4 filed on November 9, 2000).*
(a)(3) Form of Notice of Guaranteed Delivery (incorporated by reference to Exhibit 99.2 to
The AES Corporation Registration Statement on Form S-4 filed on November 9, 2000).*
(a)(4) Form of Letter to Brokers, Dealers, Commercial Banks, Trust Companies and Other
Nominees (incorporated by reference to Exhibit 99.3 to The AES Corporation
Registration Statement on Form S-4 filed on November 9, 2000).*
(a)(5) Form of Letter to Clients for use by Brokers, Dealers, Commercial Banks, Trust
Companies and Other Nominees (incorporated by reference to Exhibit 99.4 to The AES
Corporation Registration Statement on Form S-4 filed on November 9, 2000).*
(a)(6) Guidelines for Certification of Taxpayer Identification Number on Substitute Form W-9
(incorporated by reference to Exhibit 99.5 to The AES Corporation Registration
Statement on Form S-4 filed on November 9, 2000).*
(a)(7) Summary Advertisement published in The Wall Street Journal on November 13, 2000
(incorporated by reference to Exhibit 99.6 to The AES Corporation Registration
Statement on Form S-4 filed on November 9, 2000).*
(a)(8) Press Release issued by AES on November 3, 2000 (incorporated by reference to
Exhibit 99.7 to The AES Corporation Registration Statement on Form S-4 filed on
November 9, 2000).*
(b) None.
(d) Letter Agreement between AES and Compania de Petroleos de Chile S.A., dated
November 3, 2000.*
(g) None.
(h) None.
(a)(9) Press release dated November 22, 2000.*
(a)(10) Press release dated November 28, 2000.*
(a)(11) Agreement, dated as of November 28, 2000, between AES, TotalFinaElf, and Total Gas
and Power Ventures.*
(a)(12) Press release dated December 7, 2000.*
(a)(13) Preliminary Prospectus, dated December 7, 2000, relating to AES Shares to be issued in
Offer (incorporated by reference from Amendment No. 1 to AES's Registration
Statement on S-4 filed on December 7, 2000).*
(a)(14) Press release dated December 8, 2000.*
(a)(15) Press release dated December 12, 2000.*
(a)(16) Supplement No. 1 to the Prospectus relating to AES shares to be issued in the U.S.
Offer.*
(a)(17) Press release dated December 20, 2000.*
(a)(18) Final Prospectus, dated December 22, 2000, relating to AES Shares to be issued in the
U.S. Offer (incorporated by reference from Amendment No. 4 to AES's Registration
Statement on Form S-4 filed on December 22, 2000).*
(a)(19) Press release dated December 22, 2000.
</TABLE>
* Previously filed.
