X0303 4 2010-01-28 0000091142 SMITH A O CORP AOS 0001219555 MAPES CHRISTOPHER L A. O. SMITH ELECTRICAL PRODUCTS COMPANY 531 NORTH 4TH STREET TIPP CITY OH 45371-1899 0 1 0 0 Executive Vice President Common Stock 2010-01-28 4 S 0 .466 43.28 D 14975 D Column 5 of Table 1 includes 572 shares of Common Stock acquired through automatic reinvestment of quarterly dividends under the A. O. Corporation Dividend Reinvestment Plan ("Plan"). On January 19, 2010, Christopher Mapes discontinued his participation in this Plan and the fractional shares were sold on January 28, 2010. Kenneth J. Maciolek, Attorney-in-Fact for Christopher L. Mapes 2010-02-01