NewMarket Corporation's Credit Rating Raised by S&P 
12/19/2005 

Richmond, VA, December 19, 2005 – NewMarket Corporation (NYSE:NEU), Vice President and Principal Financial Officer, David A. Fiorenza, released the following statement today.

"As many of you may have seen, Standard and Poor's Rating Services raised its ratings on our Company on December 6, 2005.  The overall corporate rating was raised to BB from BB-.  We are pleased with this acknowledgment of the progress we have made over the past several years."

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.

Some of the information contained in this press release constitutes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995.  Although NewMarket's management believes its expectations are based on reasonable assumptions within the bounds of its knowledge of its business and operations, there can be no assurance that actual results will not differ materially from expectations. Factors that could cause actual results to differ materially from expectations include, but are not limited to: timing of sales orders; gain or loss of significant customers; competition from other manufacturers; resolution of environmental liabilities; changes in the demand for our products; significant changes in new product introduction; increases in product cost; the impact of fluctuations in foreign exchange rates on reported results of operations; changes in various markets; geopolitical risks in certain of the countries in which we conduct business; the impact of consolidation of the petroleum additives industry; and other factors detailed from time to time in the reports that NewMarket files with the Securities and Exchange Commission, including the risk factors in Item 7A, "Quantitative and Qualitative Disclosures About Market Risk" of our 2004 Annual Report on Form 10-K, which is available to shareholders upon request. 

You should keep in mind that any forward-looking statement made by NewMarket in the foregoing discussion speaks only as of the date on which such forward-looking statement is made.  New risks and uncertainties come up from time to time, and it is impossible for us to predict these events or how they may affect the company.  We have no duty to, and do not intend to, update or revise the forward-looking statements in this discussion after the date hereof, except as may be required by law.  In light of these risks and uncertainties, you should keep in mind that the events described in any forward-looking statement made in this discussion, or elsewhere, might not occur.

For Investor Information, Contact:

     NewMarket Corporation, Richmond
     Investor Relations: David A. Fiorenza, 804-788-5555
     Fax: 804-788-5688
     investorrelations@newmarket.com