X0202 4 2006-12-07 0 0000075677 PACKAGING CORP OF AMERICA PKG 0001219630 MENCOFF SAMUEL M THREE FIRST NATIONAL PLAZA SUITE 3800 CHICAGO IL 60602 1 0 1 0 Common Stock, $0.01 par value 2006-12-07 4 J 0 5000000 0 D 11773010 I Through PCA Holdings LLC Common Stock, $.01 par value 2006-12-07 4 J 0 571894 0 A 571894 I Through Madison Dearborn Partners, III, L.P. Common Stock, $.01 par value 6685 I Through Emily Case Mencoff Dynasty Trust Common Stock, $.01 par value 6685 I Through Samuel Keefer Mencoff Dynasty Trust Common Stock, $.01 par value 6685 I Through George Grove Mencoff Dynasty Trust Common Stock, $.01 par value 4466 I Through Madison Dearborn Partners, LLC Common Stock, $.01 par value 63445 D Reflects a pro rata distribution of shares of common stock of the issuer by PCA Holdings LLC ("Holdings"), the record and direct beneficial owner of the shares, to its two members, Madison Dearborn Capital Partners III, L.P. ("MDCP III") and a fund affiliated with MDCP III (collectively, the "Funds") on December 7, 2006, which shares were further distributed pro rata by the Funds to their respective general and limited partners on that date. The reporting person expressly disclaims beneficial ownership of 12,369,425 shares reported in Table I as indirectly beneficially owned, except to the extent of his pecuniary interest therein, and the inclusion of these shares in this report shall not be deemed an admission of beneficial ownership of the reported shares for purposes of Section 16 or for any other purpose. Holdings is the record and direct beneficial owner of the reported securities. The shares held by Holdings may be deemed to be beneficially owned by MDCP III, the managing member of Holdings, the fund affiliated with MDCP III, Madison Dearborn Partners III, L.P. ("MDP III"), the sole general partner of MDCP III and the fund affiliated with MDCP III, and Madison Dearborn Partners, LLC ("MDP LLC"), the sole general partner of MDP III. The reporting person is a managing director and member of MDP LLC and may be deemed to have an indirect pecuniary interest in the shares owned by Holdings to the extent of the reporting person's indirect proportionate interest in Holdings. Consists of shares of common stock of the issuer received by MDP III, the sole general partner of MDCP III and the fund affiliated with MDCP III, as a result of the distribution by the Funds. MDP III is the record and beneficial owner of 571,894 shares. MDP III is the sole general partner of each of the Funds and, therefore, may be deemed to be the beneficial owner of the 11,773,010 shares held of record and beneficially owned by Holdings. The shares held by MDP III may be deemed to be beneficially owned by MDP LLC, the sole general partner of MDP III. The reporting person is a managing director and member of MDP LLC and may be deemed to have an indirect pecuniary interest in the shares owned by Holdings to the extent of the reporting person's indirect proportionate interest in Holdings. Each of the Emily Case Mencoff - Dynasty Trust, Samuel Keefer Mencoff - Dynasty Trust and George Grove Mencoff - Dynasty Trust (collectively, the "Trusts") is the record and direct beneficial owner of the reported securities, which are held in trust for the benefit of the reporting person's children. The reporting person's spouse is a trustee of the Trusts. /s/ SAMUEL M. MENCOFF 2006-12-11