================================================================================
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
SCHEDULE 13G
AMENDMENT NO 1
UNDER THE SECURITIES EXCHANGE ACT OF 1934
AmerisourceBergen Corporation
--------------------------------------------------------------------------------
(Name of Issuer)
Common Stock, no par value
--------------------------------------------------------------------------------
(Title of Class of Securities)
03073E105
--------------------------------------------------------------------------------
(CUSIP Number)
April 30, 2006
--------------------------------------------------------------------------------
(Date of Event which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule
is filed:
[ ] Rule 13d-1(c) [ ] Rule 13d-1(d) [X] Rule 13d-1(b)
* The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page.
The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).
================================================================================
-------------------------- --------------------------
CUSIP NO. 03073E105 SCHEDULE 13G PAGE 2 OF 6 PAGES
--------------------------------------------------------------------------------
1. NAME OF REPORTING PERSON/S.S. OR I.R.S. IDENTIFICATION
NO. OF ABOVE PERSON
PZENA INVESTMENT MANAGEMENT, LLC
--------------------------------------------------------------------------------
2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (A) [ ]
(B) [ ]
--------------------------------------------------------------------------------
3. SEC USE ONLY
--------------------------------------------------------------------------------
4. CITIZENSHIP OR PLACE OF ORGANIZATION
DELAWARE
--------------------------------------------------------------------------------
5. SOLE VOTING POWER
4,308,950
NUMBER OF --------------------------------------------------
SHARES 6. SHARED VOTING POWER
BENEFICIALLY
OWNED BY 0
EACH --------------------------------------------------
REPORTING 7. SOLE DISPOSITIVE POWER
PERSON
WITH: 9,704,475
--------------------------------------------------
8. SHARED DISPOSITIVE POWER
0
--------------------------------------------------------------------------------
9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
9,704,475
--------------------------------------------------------------------------------
10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES
CERTAIN SHARES* [ ]
--------------------------------------------------------------------------------
11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
4.64%
--------------------------------------------------------------------------------
12. TYPE OF REPORTING PERSON*
IA
================================================================================
CUSIP NO. 03073E105 SCHEDULE 13G PAGE 3 OF 6 PAGES
--------------------------------------------------------------------------------
ITEM 1.
(a) Name of Issuer: AmerisourceBergen Corp.
-------------------------------
(b) Address of Issuer's Principal Executive Offices:
1300 Morris Drive, Chesterbrook, PA 19087
-------------------------------------------
ITEM 2.
(a) Name of Person Filing: Pzena Investment Management, LLC
------------------------------------------------
(b) Address of Principal Business Office or, if none, Residence:
120 West 45th Street, 20th Floor, New York, NY 10036
------------------------------------------------------
(c) Citizenship: Delaware
---------------------
(d) Title of Class of Securities: Common Stock
-------------------
(e) CUSIP Number: 03073E105
-----------------
ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO RULE 13D-1(B), OR 13D-2(B), CHECK
WHETHER THE PERSON FILING IS A:
(a) [ ] Broker or Dealer registered under Section 15 of the Act
(b) [ ] Bank as defined in section 3(a)(6) of the Act
(c) [ ] Insurance Company as defined in section 3(a)(19) of the Act
(d) [ ] Investment Company registered under section 8 of the Investment
Company Act of 1940
(e) [X] Investment Adviser registered under section 203 of the Investment
Advisers Act or under the laws of any State
(f) [ ] Employee Benefit Plan, Pension fund which is subject to the
provisions of the Employee Retirement Income Security Act of
1974 or Endowment Fund; see Section 240.13d-1(b)(1)(ii)(F)
(g) [ ] Parent Holding Company, in accordance with Section 240.13d-1(b)
(ii)(G)(Note: See Item 7)
(h) [ ] A Savings Association as defined in Section 3(b) of the Federal
Deposit Insurance Act
(i) [ ] A Church Plan that is excluded from the definition of an
investment company under Section 3(c)(14) of the Investment
Company Act of 1940
(j) [ ] Group, in accordance with Section 240.13d-1(b)(1)(ii)(J)
If this statement is filed pursuant to Rule 240.13d-1(c), check this box [ ].
CUSIP NO. 03073E105 SCHEDULE 13G PAGE 4 OF 6 PAGES
--------------------------------------------------------------------------------
ITEM 4. OWNERSHIP
If the percent of the class owned, as of December 31 of the year covered by this
statement, or as of the last day of any month described in Rule 13d-1(b)(2), if
applicable, exceeds five percent, provide the following information as of that
date and identify those shares which there is a right to acquire.
(a) Amount Beneficially Owned: 9,704,475
--------------------------------------------------
(b) Percent of Class: 4.64%
---------------------------------------------------------
(c) Number of shares as to which such person has:
(i)sole power to vote or to direct the vote: 4,308,950
-----------------------------
(ii)shared power to vote or to direct the vote: 0
----------------------------
(iii)sole power to dispose or to direct the disposition of: 9,704,475
------------------
(iv) shared power to dispose or to direct the disposition of: 0
---------------
ITEM 5. OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS
If this statement is being filed to report the fact that as of the date hereof
the reporting person has ceased to be the beneficial owner of more than five
percent of the class of securities, check the following [X].
ITEM 6. OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON
If any other person is known to have the right to receive or the power to direct
the receipt of dividends from, or the proceeds from the sale of, such
securities, a statement to that effect should be included in response to this
item and, if such interest relates to more than five percent of the class, such
person should be identified. A listing of the shareholders of an investment
company registered under the Investment Company Act of 1940 or the beneficiaries
of employees benefit plan, pension fund or endowment fund is not required.
CLIENTS OF THE FILING INVESTMENT MANAGER HAVE THE RIGHT TO RECEIVE AND THE
ULTIMATE POWER TO DIRECT THE RECEIPT OF DIVIDENDS FROM, OR THE PROCEEDS OF SALE
OF THE SECURITIES REPORTED ON HEREINABOVE. NO INTEREST OF ANY ONE OF SUCH
CLIENTS RELATES TO MORE THAN FIVE PERCENT OF THE CLASS.
ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY
If a parent holding company has filed this schedule, pursuant to Rule
13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the
identity and the Item 3 classification of the relevant subsidiary. If a parent
holding company has filed this schedule pursuant to Rule 13d-1(c), attach an
exhibit stating the identification of the relevant subsidiary. NOT APPLICABLE.
CUSIP NO. 03073E105 SCHEDULE 13G PAGE 5 OF 6 PAGES
--------------------------------------------------------------------------------
ITEM 8. IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP
If a group has filed this schedule pursuant to Rule 13d-1(b)(ii)(J), so indicate
under Item 3(h) and attach an exhibit stating the identity and Item 3
classification of each member of the group. If a group has filed this schedule
pursuant to Rule 13d-1(d), attach an exhibit stating the identity of each member
of the group. NOT APPLICABLE.
ITEM 9. NOTICE OF DISSOLUTION OF GROUP
Notice of dissolution of a group may be furnished as an exhibit stating the date
of the dissolution and that all further filings with respect to transactions in
the security report on will be filed, if required, by members of the group, in
their individual capacity. NOT APPLICABLE.
ITEM 10. CERTIFICATION
By signing below, I certify that, to the best of my knowledge and belief, the
securities referred to above were acquired and are held in the ordinary course
of business and were not acquired and are not held for the purpose of and do not
have the effect of changing or influencing the control of the issuer of such
securities and were not acquired and are not held in connection with or as a
participant in any transaction having that purpose or effect.
CUSIP NO. 03073E105 SCHEDULE 13G PAGE 6 OF 6 PAGES
--------------------------------------------------------------------------------
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I hereby
certify that the information set forth in this statement is true, complete and
correct.
Dated as of May 9, 2006
Richard S. Pzena, Manager
-------------------------------------
NAME/TITLE