Exhibit 4.2

______________________________________________________________________________

RLI CORP., Issuer

To

DEUTSCHE BANK TRUST COMPANY AMERICAS, Trustee

SUPPLEMENTAL INDENTURE

Dated as of May 4, 2018

Senior Debt Securities

______________________________________________________________________________

Supplemental Indenture, dated as of May 4, 2018 (“Supplemental Indenture”), between RLI CORP., a Delaware corporation (“RLI Delaware”), successor by merger to RLI Corp., an Illinois corporation (“RLI Illinois”), having its principal executive office located at 9025 North Lindbergh Drive, Peoria, Illinois 61615, and DEUTSCHE BANK TRUST COMPANY AMERICAS, a New York banking corporation (the “Trustee”), having its Corporate Trust Office located at 60 Wall Street, New York, New York 10005. 

W I T N E S E T H:

WHEREAS, RLI Illinois executed and delivered to the Trustee an indenture, dated as of October 2, 2013 (the “Indenture”), providing for the issuance from time to time of its senior unsecured debentures, notes or other evidences of indebtedness, unlimited as to principal amount, to bear such rates of interest, to mature at such time or times, to be issued in one or more series and to have such other provisions as shall be fixed as thereafter provided;

WHEREAS, Section 8.1 of the Indenture provides that RLI Illinois may merge into another Person in accordance with such Section, including that the surviving Person shall expressly assume, by an indenture supplemental to the Indenture, the due and punctual payment of the principal, any premium and interest on any Additional Amounts with respect to all the Securities and the performance of every obligation in the Indenture and the Outstanding Securities on the part of RLI Illinois to be performed;

WHEREAS, Section 9.1 of the Indenture provides that RLI Illinois and the Trustee may, without obtaining the consent of any Holders of Securities or Coupons, enter indentures supplemental to the Indenture to evidence the succession of another Person to RLI Illinois, and the assumption by any such successor of the covenants of RLI Illinois contained in the Indenture and in the Securities;

WHEREAS, on May 4, 2018, pursuant to an Agreement and Plan of Merger dated May 3, 2018, RLI Illinois merged with and into RLI Delaware, with RLI Delaware as the surviving corporation

WHEREAS, all conditions necessary to authorize the execution of this Supplemental Indenture and to make this Supplemental Indenture valid and binding have been complied with or have been performed; and

WHEREAS, pursuant to Section 9.3 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture.

NOW, THEREFORE, in consideration of the foregoing and for other good and valuable consideration, the receipt of which is hereby acknowledged, RLI Delaware and the Trustee mutually covenant and agree for the equal and ratable benefit of the holders of the Securities as follows:

[Signature pages follow.]

IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be duly executed as of the date first above written.