Other Events. On August 13, 2026, the Company issued a press release reporting that the Company’s Board of Directors had declared a dividend of $3.00 per share of the Company’s common stock, payable on October 1, 2026, to Company shareholders of record at the close of business on September 15, 2026. A copy of this press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

of this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.

Other Events. On April 23, 2026, the Company issued a press release reporting that the Company’s Board of Directors had declared a dividend of $3.00 per share of the Company’s common stock, payable on July 1, 2026, to Company shareholders of record at the close of business on June 15, 2026. A copy of this press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

of this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.

Other Events. On February 26, 2026, NewMarket Corporation (the “Company”) issued a press release reporting that the Company’s Board of Directors had declared a dividend of $3.00 per share of the Company’s common stock, payable on April 1, 2026, to Company shareholders of record at the close of business on March 16, 2026. A copy of this press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

Director — Bruce R. Hazelgrove, III: Mr. Hazelgrove was elected as a director while continuing his role as Executive Vice President and Chief Administrative Officer.

Principal Accounting Officer — Susan M. Ridlehoover: Susan M. Ridlehoover was promoted to Principal Accounting Officer within the company.

of this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.

Director — Bruce C. Gottwald: The filing reports the retirement of a director, which is a routine board change and not the departure of a senior executive officer.

Controller — Ann P. Pietrantoni: The Controller and Principal Accounting Officer is resigning to pursue other opportunities, with the CFO assuming the role on an interim basis.

Other Events. On October 30, 2025, NewMarket Corporation (the “Company”) issued a press release reporting that the Company’s Board of Directors had approved raising the quarterly dividend approximately 9% from $2.75 per share on the common stock of the Company to $3.00 per share. The quarterly dividend is equivalent to an annual dividend of $12.00 per share, up from $11.00 per share. Future dividends are subject to quarterly determination and declaration by the Board of Directors. The current…

of this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.

Other Events. On August 7, 2025, NewMarket Corporation (the “Company”) issued a press release reporting that the Company’s Board of Directors had declared a dividend of $2.75 per share of the Company’s common stock, payable on October 1, 2025, to Company shareholders of record at the close of business on September 15, 2025. A copy of this press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

of this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.

Other Events. On April 24, 2025, the Company issued a press release reporting that the Company’s Board of Directors had declared a dividend of $2.75 per share of the Company’s common stock, payable on July 1, 2025, to Company shareholders of record at the close of business on June 16, 2025. A copy of this press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

of this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.

Other Events. On February 27, 2025, the Company issued a press release reporting that the Company’s Board of Directors had approved raising the quarterly dividend 10% from $2.50 per share on the common stock of the Company to $2.75 per share. The quarterly dividend is equivalent to an annual dividend of $11.00 per share, up from $10.00 per share. Future dividends are subject to quarterly determination and declaration by the Board of Directors. The current quarterly dividend is payable April 1…

of this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.

CFO — Timothy K. Fitzgerald: The filing discloses the appointment of a new CFO and his compensation, which is a significant management change but not a departure.

Other Events On December 12, 2024, the NewMarket Corporation (the “Company”) Board of Directors approved a new share repurchase program authorizing management to repurchase up to $500 million of the Company’s outstanding common stock through December 31, 2027, as market conditions warrant and covenants under the Company’s existing debt agreements permit. The new repurchase program will replace the Company’s existing $500 million repurchase program approved by the Board of Directors in October…

Other Events. On October 24, 2024, NewMarket Corporation (the “Company”) issued a press release reporting that the Company’s Board of Directors had declared a dividend of $2.50 per share of the Company’s common stock, payable on January 2, 2025, to Company shareholders of record at the close of business on December 16, 2024. A copy of this press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

of this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.

CFO — William J. Skrobacz: The CFO is retiring with a named internal successor, representing an orderly succession rather than a sudden loss of leadership.

Other Events. On August 8, 2024, NewMarket Corporation (the “Company”) issued a press release reporting that the Company’s Board of Directors had declared a dividend of $2.50 per share of the Company’s common stock, payable on October 1, 2024, to Company shareholders of record at the close of business on September 16, 2024. A copy of this press release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

of this Current Report on Form 8-K, including Exhibit 99.1, shall not be deemed “filed” for the purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such a filing.