Table of Contents 105 4(c)(2) Second Supplemental Indenture, dated as of July 15, 2008, between Alcoa Inc. and The Bank of New York Mellon Trust Company, N.A., as successor in interest to J. P. Morgan Trust Company, National Association (formerly Chase Manhattan Trust Company, National Association, as successor to PNC Bank, National Association), as Trustee, incorporated by reference to exhibit 4(c) to the Company’s Current Report on Form 8-K (Commission file number 1-3610) dated July 15, 2008. 4(c)(3) Fourth Supplemental Indenture, dated as of December 31, 2017, between Arconic Inc., a Pennsylvania corporation, Arconic Inc., a Delaware corporation, and The Bank of New York Mellon Trust Company, N.A., as trustee, incorporated by reference to exhibit 4.3 to the Company’s Current Report on Form 8-K (Commission file number 1-3610) dated January 4, 2018. 4(c)(4) Fifth Supplemental Indenture, dated as of April 16, 2020, between Howmet Aerospace Inc., a Delaware corporation, and The Bank of New York Mellon Trust Company, N.A., as trustee, incorporated by reference to exhibit 4(e) to the Company’s Registration Statement on Form S-3 (Registration Statement No. 333-237705) dated April 16, 2020. 4(c)(5) Sixth Supplemental Indenture, dated as of May 6, 2020 between the Company and The Bank of New York Mellon Trust Company, N.A., as trustee, incorporated by reference to exhibit 4.1 to the Company’s Current Report on Form 8-K (Commission file number 1-3610) dated May 6, 2020. 4(d) Form of 6.75% Bonds Due 2028, incorporated by reference to exhibit 4(d) to the Company’s Annual Report on Form 10-K (Commission file number 1-3610) for the year ended December 31, 2017. 4(e) Form of 5.90% Notes Due 2027, incorporated by reference to exhibit 4(e) to the Company’s Annual Report on Form 10-K (Commission file number 1-3610) for the year ended December 31, 2008. 4(f) Form of 5.95% Notes Due 2037, incorporated by reference to exhibit 4(f) to the Company’s Annual Report on Form 10-K (Commission file number 1-3610) for the year ended December 31, 2008. 4(g) Form of 5.87% Notes Due 2022, incorporated by reference to exhibit 4.2 to the Company’s Current Report on Form 8-K (Commission file number 1-3610) dated February 21, 2007. 4(h) Form of 5.40% Notes Due 2021, incorporated by reference to exhibit 4 to the Company’s Current Report on Form 8-K (Commission file number 1-3610) dated April 21, 2011. 4(i) Form of 5.125% Notes Due 2024, incorporated by reference to exhibit 4.5 to the Company’s Current Report on Form 8-K (Commission file number 1-3610) dated September 22, 2014. 4(j) Form of 6.875% Notes due 2025, incorporated by reference to exhibit 4.6 to the Company’s Current Report on Form 8-K (Commission file number 1-3610) dated April 24, 2020. 4(k) Howmet Aerospace Hourly Retirement Savings Plan (formerly known as the Arconic Bargaining Retirement Savings Plan and, prior to that, the Alcoa Retirement Savings Plan for Bargaining Employees), as Amended and Restated effective January 1, 2015, incorporated by reference to exhibit 4(p) to the Company’s Annual Report on Form 10-K (Commission file number 1- 3610) for the year ended December 31, 2015. 4(l) Howmet Aerospace Salaried Retirement Savings Plan (formerly known as the Arconic Salaried Retirement Savings Plan and, prior to that, the Alcoa Retirement Savings Plan for Salaried Employees), as Amended and Restated effective January 1, 2015, incorporated by reference to exhibit 4(s) to the Company’s Annual Report on Form 10-K (Commission file number 1-3610) for the year ended December 31, 2015. 4(m) Howmet Aerospace Niles Bargaining Retirement Savings Plan (formerly known as the Arconic Retirement Savings Plan for ATEP Bargaining Employees), effective January 1, 2017, incorporated by reference to exhibit 4 to Post-Effective Amendment, dated December 30, 2016, to Registration Statement No. 333-32516 on Form S-8. 4(p) Description of Arconic Inc.'s Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934, incorporated by reference to exhibit 4(p) to the Company’s Annual Report on Form 10-K (Commission file number 1-3610) for the year ended December 31, 2019. 10(a) Five-Year Revolving Credit Agreement, dated as of July 25, 2014, among Alcoa Inc., the Lenders and Issuers named therein, Citibank, N.A., as Administrative Agent for the Lenders and Issuers, and JPMorgan Chase Bank, N.A., as Syndication Agent, incorporated by reference to exhibit 10.2 to the Company’s Current Report on Form 8-K (Commission file number 1-3610) dated July 31, 2014.