Certain Common Units of Oasis Midstream Partners LP are subject to a Lock-Up Agreement Ending on 23-AUG-2021. These Common Units will be under lockup for 60 days starting from 24-JUN-2021 to 23-AUG-2021. Details: The company and its general partner’s officers and directors have agreed that, for a period of 60 days from the date of this prospectus supplement, they will not, without the prior written consent of Morgan Stanley & Co. LLC, dispose of or hedge any common units or any securities convertible into or exchangeable for common units. Morgan Stanley & Co. LLC in its sole discretion may release any of the securities subject to these lock-up agreements at any time without notice.