THE CORPORATE LIBRARY

Related Party Transactions and Outside Related Director Information

Simpson Manufacturing Co., Inc. (SSD)

3/16/2006 Proxy Information

The Company, directly and through its subsidiaries, leases or previously leased certain of its facilities from general partnerships (the “Partnerships”) wholly or partly comprising current or former directors, officers, employees and stockholders of the Company and its subsidiaries. The Partnerships, their partners, the percentage interests of such partners in the Partnerships and the properties that the Partnerships lease, or previously leased and sold, to the Company or a subsidiary, are as follows: (See page 12 of proxy for table).

Hire of Airplane

In 2003, the Company’s Chief Executive Officer leased an airplane that is managed by a charter company unrelated to the Company. The Company pays the charter company standard hourly rates when this airplane is hired for use by its Chief Executive Officer in travel between his home and Company offices or by him and other Company employees in travel on Company business. As lessee of the airplane, the Company’s Chief Executive Officer is also responsible for its maintenance and he receives a portion of each payment to the charter company for its use, whether by the Company or others. The total cost to the Company, including the Company’s Chief Executive Officer’s compensation, was approximately $260,000 in 2005. The independent members of the Board of Directors unanimously approved this arrangement. The Company computes the compensation cost of the use of airplanes using the Standard Industrial Fare Level (“SIFL”) tables prescribed under applicable Internal Revenue Service regulations.

Other Related Party Transactions

In February 2005, the Company paid $50,000 to the California College of the Arts (“CCA”) to sponsor the development of a unique interdisciplinary course. The Company’s Chairman, Barclay Simpson, is the Vice Chairman of CCA’s Board of Trustees. The independent members of the Board of Directors approved the sponsorship of this course.

3/25/2005 Proxy Information

The Company, directly and through its subsidiaries, leases or previously leased certain of its facilities from general partnerships (the “Partnerships”) wholly or partly comprising current or former directors, officers, employees and stockholders of the Company and its subsidiaries. The Partnerships, their partners, the percentage interests of such partners in the Partnerships and the properties that the Partnerships lease, or previously leased and sold, to the Company or a subsidiary, are as follows: (Table on page 11 of proxy)

Aggregate lease payments by the Company and its subsidiaries to the Partnerships in 2004, 2003 and 2002 were, and the terms of the leases will expire, as follows: (Table on page 12 of proxy)

The leases with the Partnerships are expected to continue until the expiration of the respective terms of the leases, and they may be renewed. The Company’s future rent obligations under the continuing leases are expected to be consistent with the rents paid in 2004, subject to adjustments as provided in certain of the leases.

If and when any lease is proposed to be amended or renewed or any property subject to any lease is proposed to be purchased by the Company, the Company will enter into such transaction only with the approval of a majority of the directors of the Company who are not employees or officers of the Company and who are not partners of any of the Partnerships and only after such directors satisfy themselves that such transaction will be fair, just and reasonable as to the Company, beneficial to the Company and on terms reasonably consistent with the terms available from unrelated parties in similar transactions negotiated at arm’s length.

In January 2005, Michael Petrovic was appointed as an officer of Simpson Strong-Tie Canada, Limited (“SSTC”), a wholly-owned subsidiary of Simpson Strong-Tie. Mr. Petrovic was an owner of MGA Construction Hardware & Steel Fabricating Limited and MGA Connectors Limited, which SSTC acquired in 2003, and is a co-lessor of the property that SSTC leases in Maple Ridge, British Columbia. SSTC estimates that it will pay approximately $150,000 per year to lease the property from Mr. Petrovic and his associates. The lease expires in 2007.

The Company does not intend in the future to lease from any of the Partnerships or any other entities controlled by any of its directors, officers or employees any facilities that are not on or adjacent to the property subject to the existing leases.

Hire of Airplane

In 2003, the Company’s Chief Executive Officer leased an airplane that is managed by a charter company unrelated to the Company. The Company pays the charter company standard hourly rates when this airplane is hired for use by its Chief Executive Officer in travel between his home and Company offices or by him and other Company employees in travel on Company business. As lessee of the airplane, the Company’s Chief Executive Officer is also responsible for its maintenance and he receives a portion of each payment to the charter company for its use, whether by the Company or others. The total cost to the Company, including the Company’s Chief Executive Officer’s compensation, was approximately $380,000 in 2004. The independent members of the Board of Directors unanimously approved this arrangement. The Company computes the compensation cost of the use of airplanes using the Standard Industrial Fair Level (“SIFL”) tables prescribed under applicable Internal Revenue Service regulations.

Purchase of Artwork

In 2004, the Company paid approximately $4,000 to Barclay Simpson Fine Arts, an art gallery owned by the Company’s Chairman, for artwork to decorate the Company’s offices. The independent members of the Board of Directors approved these purchases after a review of an independent appraisal and a review of the cost of comparable artwork.

Other Related Party Transactions

In December 2004, the Company made a donation in the amount or $5,000 to the African American Experience Fund of the National Park Foundation, whose Chairman is Barry Lawson Williams, a director of the Company. The independent members of the Board of Directors, with Director Williams abstaining, approved this donation.

In February 2005, the Company paid $50,000 to the California College of the Arts (“CCA”) to sponsor the development of a unique interdisciplinary course. The Company’s Chairman, Barclay Simpson, is the Vice Chairman of CCA’s Board of Trustees. The independent members of the Board of Directors approved the sponsorship of this course.

3/5/2004 Proxy Information

Real Estate Transactions

The Company, directly and through its subsidiaries, leases or previously leased certain of its facilities from general partnerships (the "Partnerships") wholly or partly comprising current or former directors, officers, employees and stockholders of the Company and its subsidiaries. The Partnerships, their partners, the percentage interests of such partners in the Partnerships and the properties that the Partnerships lease, or previously leased and sold, to the Company or a subsidiary, are as follows:

Partnership Partners (percentage interests) Property Location

Simpson Investment Company ("SIC") - Barclay Simpson (77%), John B. Simpson (5%), Anne Simpson Gattis (5%), Jean D. Simpson (5%), Jeffrey P. Gainsborough (2%), Julie Marie Simpson (2%), Elizabeth Simpson Murray (2%) and Amy Simpson (2%) - San Leandro, California

Doolittle Investors - Barclay and Sharon Simpson (25.51%), SIC (25.51%), Everett H. Johnston Family Trust (23.13%), Judy F. Oliphant, Successor Trustee of the Oliphant Family Revocable Trust Agreement Dated January 27, 1993 (Survivors Trust) ("Oliphant Trust") (20.61%), and Thomas J Fitzmyers (5.24%), - San Leandro, California

Columbus-Westbelt Investment Co. - Barclay and Sharon Simpson (13.31%), Jeffrey P. Gainsborough (11.01%), Julie Marie Simpson (11.01%), Elizabeth Simpson Murray (11.01%) and Amy Simpson (11.01%), Everett H. Johnston Family Trust (5.54%), Oliphant Trust (5.54%), Tyrell T. Gilb Marital Trust (5.54%), Doyle E. Norman (5.54%), Robert J. Phelan (5.54%), Richard C. Perkins Trust (5.48%), Stephen P. Eberhard (5.05%), Stephen B. Lamson (3.32%) and Thomas J Fitzmyers (1.10%), - Columbus, Ohio

Vacaville Investors - Everett H. Johnston Family Trust (49.90%), SIC (27.50%), Oliphant Trust (12.47%), Barclay and Sharon Simpson (4.57%), Richard C. Perkins Trust (4.43%) and Thomas J Fitzmyers (1.13%), - Vacaville, California

Vicksburg Investors - Everett H. Johnston Family Trust (41.17%), Barclay and Sharon Simpson (33.92%), Oliphant Trust (12.61%), Richard C. Perkins Trust (6.28%) and Thomas J Fitzmyers (6.02%) - Vicksburg, Mississippi

Barclay Simpson is the managing partner of SIC, a general partnership of Mr. Simpson and his seven adult children. Everett H. Johnston, formerly a director and executive officer of the Company (now retired), is the managing partner of each Partnership other than SIC. Stephen P. Eberhard, is an officer of SDV and Robert J. Phelan is an officer of SST. Richard C. Perkins (retired) and Doyle E. Norman (retired) and Tyrell T. Gilb (deceased) formerly were employees of the Company, as was Judy F. Oliphant's late husband, Hugh Oliphant. Sharon Simpson is Barclay Simpson's wife.

Aggregate lease payments by the Company and its subsidiaries to the Partnerships in 2003, 2002 and 2001 were, and the terms of the leases will expire, as follows:

Partnership Lease Payments Lease Expiration Date 2003 2002 2001 SIC(1) $ — $ — $ 82,331 (1) Doolittle Investors 367,992 367,992 253,080 12/31/09 Columbus Westbelt Investment Co. 626,328 626,328 626,328 9/30/05 Vacaville Investors 454,874 452,736 438,898 11/30/07 Vicksburg Investors(2) 64,226 385,356 368,543 (2)

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(1) In January 2001, the Company exercised its option to purchase the property leased from SIC. The transaction closed in June 2001.

(2) This building was sold by the Partnership to an unrelated party in February 2003. The lease expired in November 2003.

The leases with the Partnerships are expected to continue until the expiration of the respective terms of the leases, and they may be renewed. The Company's future rent obligations under the continuing leases are expected to be consistent with the rents paid in 2003, subject to adjustments as provided in certain of the leases.

If and when any lease is proposed to be amended or renewed or any property subject to any lease is proposed to be purchased by the Company, the Company will enter into such transaction only with the approval of a majority of the directors of the Company who are not employees or officers of the Company and who are not partners of any of the Partnerships and only after such directors satisfy themselves that such transaction will be fair, just and reasonable as to the Company, beneficial to the Company and on terms reasonably consistent with the terms available from unrelated parties in similar transactions negotiated at arm's length.

The Company does not intend in the future to lease from any of the Partnerships or any other entities controlled by any of its directors, officers or employees any facilities that are not on or adjacent to the property subject to the existing leases.

Repurchase of Common Stock

In 2003, the Company purchased 500,000 shares of its Common Stock for approximately $23,525,000 from the Simpson PSB Fund to offset the dilution of stock options granted in 2003. The Chairman and the President and Chief Executive Officer of the Company, who are directors and significant stockholders of the Company, serve as directors and officers of the Simpson PSB Fund (a charitable organization). The price per share was $47.05, which was the closing price on the day before the transaction less $0.50. The independent members of the Board of Directors unanimously approved this transaction.

Hire of Airplane

In 2003, the Company's Chief Executive Officer leased an airplane that is managed by a charter company unrelated to the Company. The Company pays the charter company standard hourly rates when this airplane is hired for use by its Chief Executive Officer in travel between his home and Company offices or by him and other Company employees in travel on Company business. As lessee of the airplane, the Company's Chief Executive Officer is also responsible for its maintenance and he receives a portion of each payment to the charter company for its use, whether by the Company or others. The total cost to the Company, including the Company's Chief Executive Officer's compensation, was approximately $352,000 in 2003.

Purchase of Artwork

In 2003, the Company paid approximately $90,000 to Barclay Simpson Fine Arts, an art gallery owned by the Company's Chairman, for artwork to decorate the Company's offices. In January 2004, the Company made an additional purchase of approximately $4,000. The independent members of the Board of Directors approved these purchases after a review of an independent appraisal and a review of the cost of comparable artwork.