NewMarket Corporation Announces Odd-Lot Program 

RICHMOND, Va., May 26, 2005 – NewMarket Corporation (NYSE:NEU) announced today a voluntary sales program for shareholders of fewer than 100 shares of NewMarket common stock.

Eligible participants who own fewer than 100 shares of NewMarket common stock will be offered the opportunity to sell all of their NewMarket shares of NewMarket common stock.  NewMarket common stock was formerly traded as Ethyl Corporation. The price per share for such sales will be determined using a weighted average price of market trades during the pricing periods.  The program is being administered and managed by Georgeson Shareholder.

Information about the odd-lot program will be mailed directly to eligible shareholders. This offer is not conditioned on a receipt of any minimum number of tenders and the offer will expire on June 30, 2005, unless extended by NewMarket.  NewMarket is not recommending that odd-lot holders sell their shares of NewMarket common stock.  NewMarket encourages odd-lot holders to make their own decision as to whether to participate in this voluntary program and to contact their financial advisor for appropriate guidance.

NewMarket Corporation through its subsidiaries, Afton Chemical Corporation and Ethyl Corporation, develops, manufactures, blends, and delivers chemical additives that enhance the performance of petroleum products. From custom-formulated chemical blends to market-general additive components, the NewMarket family of companies provides the world with the technology to make fuels burn cleaner, engines run smoother and machines last longer.

Contact:  NewMarket Corporation
Richmond, Virginia Investor Relations
David A. Fiorenza
Tel: 804-788-5555 Fax: 804-788-5688