X0306 4 2015-10-28 1 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 2015-10-28 4 D 0 10500 34.00 D 19889 D Common Stock 2015-10-28 4 D 0 8800 34.00 D 11089 D Common Stock 2015-10-28 4 D 0 5400 34.00 D 5689 D Common Stock 2015-10-28 4 D 0 14 34.00 D 5675 D Common Stock 2015-10-28 4 D 0 5675 34.00 D 0 D Employee Stock Options (right to buy) 33.17 2015-10-28 4 D 0 5000 0.83 D 2020-11-01 Common Stock 5000 0 D Employee Stock Options (right to buy) 36.51 2015-10-28 4 D 0 10700 0.00 D 2021-02-08 Common Stock 10700 0 D Employee Stock Options (right to buy) 30.21 2015-10-28 4 D 0 10200 3.79 D 2022-02-14 Common Stock 10200 0 D Employee Stock Options (right to buy) 27.32 2015-10-28 4 D 0 12500 6.68 D 2023-02-12 Common Stock 12500 0 D Employee Stock Options (right to buy) 32.24 2015-10-28 4 D 0 12500 1.76 D 2024-02-11 Common Stock 12500 0 D Employee Stock Options (right to buy) 29.04 2015-10-28 4 D 0 17100 4.96 D 2025-02-10 Common Stock 17100 0 D Half of these performance units were disposed of pursuant to a merger agreement, dated May 31, 2015, by and among Duke Acquisition Holdings, LLC, Duke Acquisition, Inc., MacDermid Americas Acquisitions, Inc., and the Issuer (the "Merger Agreement") in exchange for the right to receive $34.00 in cash per performance unit, representing payout for the applicable performance share award at target performance level, plus any earned cash dividend equivalents, with the remaining performance units forfeited back to the Issuer for no consideration. Includes 14 dividend equivalents acquired on outstanding performance units awards through an exempt dividend equivalent feature. Performance units disposed of pursuant to the Merger Agreement in exchange for the right to receive $34.00 in cash per performance unit, representing payout for the applicable performance share award at target performance level. Dividend equivalents on outstanding performance units awards disposed of pursuant to the Merger Agreement in exchange for the right to receive $34.00 in cash per dividend equivalent. Disposed of pursuant to the Merger Agreement in exchange for the right to receive $34.00 in cash per share. These options were fully vested. These options vested or were to vest in three equal installments on February 12, 2014, 2015, and 2016. These options vested or were to vest in three equal installments on February 11, 2015, 2016, and 2017. These options were to vest in three equal installments on February 10, 2016, 2017 and 2018. Disposed of pursuant to the Merger Agreement in exchange for a cash payment approximately equal to the difference (if positive) between $34.00 and the exercise price of the stock option multiplied by the number of outstanding shares (both vested and unvested) subject to the stock option. /s/ Valerie Gentile Sachs, as Attorney-In-Fact 2015-10-30