X0306 4 2020-11-13 1 0001600470 Montage Resources Corp MR 0001504103 EnCap Energy Capital Fund VIII, L.P. 1100 LOUISIANA STREET, SUITE 4900 HOUSTON TX 77002 0 0 1 0 0001537403 EnCap Energy Capital Fund VIII Co-Investors, L.P. 1100 LOUISIANA STREET, SUITE 4900 HOUSTON TX 77002 0 0 1 0 0001565683 EnCap Energy Capital Fund IX, L.P. 1100 LOUISIANA STREET, SUITE 4900 HOUSTON TX 77002 0 0 1 0 0001726182 EnCap Partners GP, LLC 1100 LOUISIANA STREET, SUITE 4900 HOUSTON TX 77002 0 0 1 0 0001766953 TPR Residual Assets, LLC 1100 LOUISIANA STREET, SUITE 4900 HOUSTON TX 77002 0 0 1 0 Common Stock 2020-11-13 4 D 0 2694673 D 0 I See footnote Common Stock 2020-11-13 4 D 0 4856485 D 0 I See footnote Common Stock 2020-11-13 4 D 0 3979173 D 0 I See footnote Common Stock 2020-11-13 4 D 0 2521573 D 0 I See footnote On November 13, 2020, pursuant to the Agreement and Plan of Merger dated as of August 12, 2020 (the "Merger Agreement"), by and among Montage Resources Corporation (the "Issuer") and Southwestern Energy Company ("Southwestern"), the Issuer merged with and into Southwestern, with Southwestern continuing as the surviving corporation (the "Merger"). Pursuant to the Merger Agreement, each issued and outstanding share of common stock of the Issuer, par value $0.01 per share, outstanding as of immediately prior to the effective time of the Merger was converted into the right to receive 1.8656 shares of Southwestern common stock, par value $0.01 per share ("Southwestern Common Stock"). On November 12, 2020 (the day prior to the effective time of the Merger), the closing price of one share of Southwestern Common Stock was $2.86. The reporting persons disclaim beneficial ownership of the reported securities except to the extent of such reporting person's pecuniary interest therein, and this report shall not be deemed an admission that such reporting person is the beneficial owner of the reported securities for purposes of Section 16 or for any other purpose. These securities were directly held by EnCap Energy Capital Fund VIII Co-Investors, L.P. ("EnCap Fund VIII Co-Invest"). EnCap Partners GP, LLC ("EnCap Partners GP") is the sole general partner of EnCap Partners, LP ("EnCap Partners"), which is the managing member of EnCap Investments Holdings, LLC ("EnCap Holdings"), which is the sole member of EnCap Investments Holdings Blocker, LLC ("EnCap Holdings Blocker"). EnCap Holdings Blocker is (i) the sole member of EnCap Investments GP, L.L.C. ("EnCap Investments GP"), which is the sole general partner of EnCap Investments L.P. ("EnCap Investments LP"), and (ii) the sole limited partner of EnCap Investments LP. EnCap Investments LP is the general partner of EnCap Equity Fund VIII GP, L.P. ("EnCap Fund VIII GP"), the sole general partner of EnCap Fund VIII Co-Invest. (Continued from footnote 4) Therefore, EnCap Partners GP, EnCap Partners, EnCap Holdings, EnCap Holdings Blocker, EnCap Investments GP, EnCap Investments LP and EnCap Fund VIII GP may be deemed to have beneficially owned these securities. These securities were directly held by EnCap Energy Capital Fund IX, L.P ("EnCap Fund IX"). EnCap Partners GP is the sole general partner of EnCap Partners, which is the managing member of EnCap Holdings, which is the sole member of EnCap Holdings Blocker. EnCap Holdings Blocker is the sole member of EnCap Investments GP, which is the sole general partner of EnCap Investments LP. EnCap Investments LP is the general partner of EnCap Equity Fund IX GP, L.P. ("EnCap Fund IX GP"), the sole general partner of EnCap Fund IX. Therefore, EnCap Partners GP, EnCap Partners, EnCap Holdings, EnCap Holdings Blocker, EnCap Investments GP, EnCap Investments LP and EnCap Fund IX GP may be deemed to have beneficially owned these securities. These securities were directly held by EnCap Energy Capital Fund VIII, L.P. ("EnCap Fund VIII"). EnCap Partners GP is the sole general partner of EnCap Partners, which is the managing member of EnCap Holdings, which is the sole member of EnCap Holdings Blocker. EnCap Holdings Blocker is the sole member of EnCap Investments GP, which is the sole general partner of EnCap Investments LP. EnCap Investments LP is the general partner of EnCap Equity Fund VIII GP, the sole general partner of EnCap Fund VIII Co-Invest. Therefore, EnCap Partners GP, EnCap Partners, EnCap Holdings, EnCap Holdings Blocker, EnCap Investments GP, EnCap Investments LP and EnCap Fund VIII GP may be deemed to have beneficially owned these securities. These securities were directly held by TPR Residual Assets, LLC ("TPR Residual"). TPR Residual is member-managed by EnCap Fund IX. Therefore, EnCap Fund IX may be deemed to have the power to vote or direct the vote or to dispose or direct the disposition of the shares owned by TPR Residual. This form represents an Exit Form 4 due to the merger of the Issuer with and into Southwestern. Exhibit List Exhibit 99 - Joint Filer Information EnCap Energy Capital Fund VIII, L.P., By: EnCap Equity Fund VIII GP, L.P., its general partner, EnCap Investments L.P., its general partner, EnCap Investments GP, L.L.C., its general partner, /s/ Douglas E. Swanson, Jr., Managing Director 2020-11-13