X0306 4 2021-02-08 0000091142 SMITH A O CORP AOS 0001507959 Heideman Robert J LLOYD R. SMITH CORPORATE TECHNOLOGY CNTR 11000 WEST PARK PLACE MILWAUKEE WI 53224 0 1 0 0 Senior VP, CTO Common Stock 2021-02-10 4 M 0 7336 50.16 A 16059 D Common Stock 2021-02-10 4 S 0 7336 61.0187 D 8723 D Employee Stock Options (Right to Buy) 60.82 2021-02-08 4 A 0 9890 0 A 2031-02-08 Common Stock 9890 59621 D Employee Stock Options (Right to Buy) 50.16 2021-02-10 4 M 0 7336 0 D 2027-02-13 Common Stock 7336 52285 D Restricted Stock Units 60.82 2021-02-08 4 A 0 2280 0 A Common Stock 2280 11290 D The price in Column 4 is a weighted average price. The prices actually received ranged from $60.750 to $61.505. The reporting person has provided to the issuer, and will provide to any security holder of the issuer, or the SEC staff, upon request, information regarding the number of shares sold at each price within the range for all transactions reported on this Form 4 utilizing an average weighted price. The employee stock options were granted on 02/08/2021 under the A. O. Smith Combined Incentive Compensation Plan, a transaction exempt under Rule 16b-3. The options become exercisable in three annual installments of 1/3 of the award starting on 02/08/2022. The employee stock options were granted on 02/13/2017 under the A. O. Smith Combined Incentive Compensation Plan, a transaction exempt under Rule 16b-3. The options became exercisable in three annual installments of 1/3 of the award starting on 02/13/2018. The restricted stock units were granted on 02/08/2021 under the A. O. Smith Combined Incentive Compensation Plan, a transaction exempt under Rule 16b-3. The restricted stock units become payable in Common Stock on the vesting date of 02/08/2024. James F. Stern, Attorney-in-Fact for Robert J. Heideman 2021-02-10