X0306 4 2020-03-05 0001005284 UNIVERSAL DISPLAY CORP \PA\ OLED 0001423446 Mahon Janice K C/O UNIVERSAL DISPLAY CORPORATION 375 PHILLIPS BLVD. EWING NJ 08618 0 1 0 0 VP of Tech Commercialization Common Stock 2020-03-05 4 F 0 126 160.13 D 28246 D Common Stock 2020-03-06 4 F 0 130 155.85 D 28116 D Common Stock 2020-03-06 4 A 0 11165 0.0 A 39281 D Common Stock 2020-03-07 4 F 0 131 155.85 D 39150 D Common Stock 2020-03-07 4 A 0 1184 0.0 A 40334 D Common Stock 2020-03-07 4 F 0 403 155.85 D 39931 D Common Stock 2020-03-08 4 F 0 2937 155.85 D 36994 D These shares were withheld to satisfy a tax liability in connection with the vesting on March 5, 2020 of 322 shares of restricted stock previously granted to Ms. Mahon. Includes 21 shares acquired under the Universal Display Corporation Employee Stock Purchase Plan. These shares were withheld to satisfy a tax liability in connection with the vesting on March 6, 2020 of 384 shares of restricted stock previously granted to Ms. Mahon. These units were granted to Ms. Mahon under the Company's Long Term Incentive Plan as part of her 2020 compensation and are subject to a time-based restriction, with one-third of the total unit amount vesting on each of March 6, 2021, 2022, and 2023. These shares were withheld to satisfy a tax liability in connection with the vesting on March 7, 2020 of 394 shares of restricted stock previously granted to Ms. Mahon. These shares were granted to Ms. Mahon as performance units under the Company's Long Term Incentive Plan as part of her 2017 compensation and vested on March 7, 2020 subject to the satisfaction of certain performance conditions, which our Compensation Committee certified on February 13, 2020 as having occurred. These shares were withheld to satisfy a tax liability in connection with the vesting on March 7, 2020 of 1,184 shares of restricted stock previously granted to Ms. Mahon. These shares were withheld to satisfy a tax liability in connection with the vesting on March 8, 2020 of 7,000 shares of restricted stock previously granted to Ms. Mahon. /s/ Janice K. Mahon (by Mauro Premutico as power of attorney) 2020-03-09