X0305 4 2012-04-16 0000091142 SMITH A O CORP AOS 0001196442 WOLF IDELLE K A. O. SMITH CORPORATION 11270 WEST PARK PLACE MILWAUKEE WI 53224 1 0 0 0 Restricted Stock Units 44.24 2012-04-16 4 A 0 2035 0 A Common Stock 2035 2035 D Payment of portion of retainer in Restricted Stock Units under the A. O. Smith Nonqualified Deferred Compensation Plan based on the market price of the Common Stock on April 16, 2012. The Plan permits the participant to defer the receipt of the award, and Ms. Wolf has made a deferral. James F. Stern, Attorney-in-Fact for Idelle K. Wolf 2012-04-17