DEFA 14A

Schedule 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of

the Securities Exchange Act of 1934 (Amendment No. )

Filed by the Registrant ☒

Filed by a party other than the Registrant ☐

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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 Section 24 0.14a-12

RLI CORP.

...................................................................................................................................................................................

(Name of Registrant as Specified In Its Charter)

...................................................................................................................................................................................

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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*** Exercise Your Right to Vote *** Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to Be Held on May 7, 2020. RLI CORP. Meeting InfMeeting Informationormation Meeting Type: Annual Meeting For holders as of: March 9, 2020 Date: May 7, 2020 Time: 11:00 AM Location: Meeting live via the Internet-please visit www.virtualshareholdermeeting.com/rli2020. The company will be hosting the meeting live via the Internet this year. To attend the meeting via the Internet please visit www.virtualshareholdermeeting.com/rli2020 and be sure to have the information that is printed in the box marked by the arrow XXXX XXXX XXXX XXXX (located on the following page). RLI CORP. 9025 NORTH LINDBERGH DRIVE PEORIA, IL 61615 You are receiving this communication because you hold shares in the company named above. This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side). We encourage you to access and review all of the important information contained in the proxy materials before voting. See the reverse side of this notice to obtain proxy materials and voting instructions. D01502-P33523

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*** Exercise Your Right to Vote *** Important Notice Regarding the Availability of Proxy Materials for the Shareholder Meeting to Be Held on May 7, 2020. RLI CORP. For holders as of:March 9, 2020 Date: May 7, 2020 Time: 2:00 PM Location: Mwwt. wH.avwirlteuyalCshoaurnethroyldCelrumb eeting.com/rli2020. The companyPewoilrliab,eILh6o1s6ti1n4g the meeting live via the Internet RLI CORP. 9025 NORTH LINDBERGH DRIVE PEORIA, IL 61615 You are receiving this communication because you hold shares in the company named above. This is not a ballot. You cannot use this notice to vote these shares. This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. You may view the proxy materials online at www.proxyvote.com or easily request a paper copy (see reverse side). We encourage you to access and review all of the important information contained in the proxy materials before voting. proxy materials and voting instructions. D01502-P33523 See the reverse side of this notice to obtain Meeting Information Meeting TTyyppee::Annual Meeting Date: May 7, 2020Time: 11:00 AM Location: Meeting live via the Internet-please visit 7724 North Knoxville Avenue this year. To attend the meeting via the Internet please visit www.virtualshareholdermeeting.com/rli2020 and be sure to have the information that is printed in the box marked by the arrow (located on the following page). XXXX XXXX XXXX XXXX

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Before You Vote How to Access the Proxy Materials How To Vote Please Choose One of the Following Voting Methods D01503-P33523 Vote By Internet: Before The Meeting: Go to www.proxyvote.com. Have the information that is printed in the box marked by the arrow (located on the following page) available and follow the instructions. During The Meeting: Go to www.virtualshareholdermeeting.com/rli2020. Have the information that is printed in the box marked by the arrow(located on the following page) available and follow the instructions. Vote By Mail: You can vote by mail by requesting a paper copy of the materials, which will include a proxy card. XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX Proxy Materials Available to VIEW or RECEIVE: NOTICE AND PROXY STATEMENTANNUAL REPORT How to View Online: Have the information that is printed in the box marked by the arrow(located on the following page) and visit: www.proxyvote.com. How to Request and Receive a PAPER or E-MAIL Copy: If you want to receive a paper or e-mail copy of these documents, you must request one. There is NO charge for requesting a copy. Please choose one of the following methods to make your request: 1) BY INTERNET:www.proxyvote.com 2) BY TELEPHONE:1-800-579-1639 3) BY E-MAIL*:sendmaterial@proxyvote.com * If requesting materials by e-mail, please send a blank e-mail with the information that is printed in the box marked by the arrow(located on the following page) in the subject line. Requests, instructions and other inquiries sent to this e-mail address will NOT be forwarded to your investment advisor. Please make the request as instructed above on or before April 18, 2020 to facilitate timely delivery. XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX

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The Board of Directors recommends you vote FOR the following: 1. Election of Directors Nominees: 01) 02) 03) 04) 05) 06) Kaj Ahlmann Michael E. Angelina John T. Baily Calvin G. Butler, Jr. David B. Duclos Susan S. Fleming 07) 08) 09) 10) 11) Jordan W. Graham Jonathan E. Michael Robert P. Restrepo, Jr. Debbie S. Roberts Michael J. Stone The Board of Directors recommends you vote FOR proposals 2, 3, and 4. 2. Approve the amendment to the Company's Amended and Restated Certificate of Incorporation increasing the number of authorized shares of Common Stock. Advisory vote to approve executive compensation (the "Say-on-Pay" vote). 3. 4. Ratify the selection of Deloitte & Touche LLP as the Company's Independent Registered Public Accounting Firm. NOTE: This proxy also grants the Proxies the ability to vote in their discretion upon other matters as may properly come before the meeting. D01504-P33523 Voting Items

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The Board of Directors recommends you vote FOR the following: 1. Election of Directors Nominees: 01) 02) 03) 04) 05) 06) Kaj Ahlmann Michael E. Angelina John T. Baily Calvin G. Butler, Jr. David B. Duclos Susan S. Fleming 07) 08) 09) 10) 11) Jordan W. Graham Jonathan E. Michael Robert P. Restrepo, Jr. Debbie S. Roberts Michael J. Stone The Board of Directors recommends you vote FOR proposals 2, 3, and 4. 2. Approve the amendment to the Company's Amended and Restated Certificate of Incorporation increasing the number of authorized shares of Common Stock. Advisory vote to approve executive compensation (the "Say-on-Pay" vote). 3. 4. Ratify the selection of Deloitte & Touche LLP as the Company's Independent Registered Public Accounting Firm. NOTE: This proxy also grants the Trustee the ability to vote in its discretion upon other matters as may properly come before the meeting. D01505-P33523 Voting Items