================================================================================ PROSPECTUS SUPPLEMENT (TO PROSPECTUS DATED APRIL 16, 1999) ================================================================================ 922 SHARES COMMON STOCK KEY ENERGY SERVICES, INC. --------------------- --------------------------------------------------------------------------- Neither the SEC nor any state securities commission has approved these securities or determined that this prospectus supplement is accurate or complete. Any representation to the contrary is a criminal offense. --------------------------------------------------------------------------- --------------------- The Shares are being issued and delivered to Duane O. Nelson and Alice Lynn Nelson pursuant to the exercise of a Common Stock Purchase Warrant dated as of March 28, 1996 ("Warrant") to purchase 922 shares of common stock. The exercise price pursuant to the terms of the Warrant is $6.75 per share. The Shares are not being issued through underwriters, agents or dealers. No fees or commissions are being paid in connection with the issuance of the Shares. ================================================================================ The date of this Prospectus Supplement is March 9, 2001.