UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the Securities

Exchange Act of 1934

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☐	Preliminary Proxy Statement	☐	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))
☐	Definitive Proxy Statement
☒	Definitive Additional Materials
☐	Soliciting Material Pursuant to §240.14a-12

INNOSPEC INC.

(Name of Registrant as Specified In Its Charter)

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Innospec C 1234567890 IMPORTANT ANNUAL MEETING INFORMATION 000004 ENDORSEMENT LINE SACKPACK MR A SAMPLE DESIGNATION (IF ANY) ADD 1 ADD 2 ADD 3 ADD 4 ADD 5 ADD 6 Vote by Internet Go to www.envisionreports.com/iosp Or scan the QR code with your smartphone Follow the steps outlined on the secure website Innospec Inc. Stockholder Meeting Notice 1234 5678 9012 345 Important Notice Regarding the Availability of Proxy Materials for the Innospec Inc. Stockholder Meeting to be Held on May 9, 2018 Under the Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the annual stockholders’ meeting are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the annual meeting are on the reverse side. Your vote is important This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The Proxy Statement and Annual Report on Form 10-K are available at: www.envisionreports.com/iosp Easy Online Access A Convenient Way to View Proxy Materials and Vote When you go online to view materials, you can also vote your shares. Step 1: Go to www.envisionreports.com/iosp to view the materials. Step 2: Click on Cast Your Vote or Request Materials. Step 3: Follow the instructions on the screen to log in. Step 4: Make your selection as instructed on each screen to select delivery preferences and vote. When you go online, you can also help the environment by consenting to receive electronic delivery of future materials. Obtaining a Copy of the Proxy Materials If you want to receive a paper or e mail copy of these documents, you must request one. There is no charge to you for requesting a copy. Please make your request for a copy as instructed on the reverse side on or before April 24, 2018 to facilitate timely delivery. 2NOT COY + 02S91B

Innospec Inc. Stockholder Meeting Notice Innospec Inc.’s Annual Meeting of Stockholders will be held on Wednesday, May 9, 2018 at The Four Seasons, 1435 Brickell Avenue, Miami, FL 33131, at 10:00 a.m. Eastern Daylight Time. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board of Directors recommends a vote FOR all nominees and FOR Proposals 2, 3, 4 and 5: 1. Re-election of Directors – Milton C. Blackmore and Robert I. Paller. 2. Advisory vote on executive compensation. 3. Approval of the Innospec Inc. 2018 Omnibus Long-Term Incentive Plan. 4. Approval of the Innospec Inc. Sharesave Plan 2008 (as amended and restated). 5. Ratification of the Company’s independent public accounting firm for 2018. 6. Any other business. PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must vote online or request a paper copy of the proxy materials to receive a proxy card. If you wish to attend and vote at the meeting, please bring this notice with you.