X0306 4 2014-03-07 0 0000899723 OM GROUP INC OMG 0001504552 Johnson Michael V. FLATS EAST BANK BUILDING 950 MAIN AVENUE, SUITE 1300 CLEVELAND OH 44113 0 1 0 0 Vice President - HR Common Stock 2015-02-14 4 F 0 1202 29.78 D 37153 D Common Stock 2015-02-14 4 X 0 33 A 37186 D Dividend Equivalent Rights 2014-03-07 4 A 0 7 0.00 A Common Stock 7 7 D Dividend Equivalent Rights 2014-06-06 4 A 0 8 0.00 A Common Stock 8 15 D Dividend Equivalent Rights 2014-09-05 4 A 0 9 0.00 A Common Stock 9 24 D Dividend Equivalent Rights 2014-12-05 4 A 0 9 0.00 A Common Stock 9 33 D Dividend Equivalent Rights 2015-02-14 4 X 0 33 D Common Stock 33 0 D This field is not applicable. This reflects the surrender of shares to OM Group, Inc. to pay taxes applicable to the vesting of restricted stock units in accordance with the applicable long-term incentive plan previously approved by the stockholders of OM Group, Inc. and the related agreement previously approved by the Compensation Committee of the Board of Directors of OM Group, Inc. Settlement of dividend equivalent rights in connection with the vesting of restricted stock units. The rights accrued when and as dividends were paid on OM Group, Inc. Common Stock and vested with the restricted stock units to which they are related. Each dividend equivalent right is the economic equivalent of one share of OM Group Common Stock. The dividend equivalent rights accrued on restricted stock units and vest proportionately with the restricted stock units to which they relate. Each dividend equivalent right is the economic equivalent of one share of OM Group, Inc. Common Stock. /s/ Michael V. Johnson, by Cipriano S. Beredo as attorney-in-fact 2015-02-18