(13) Equity Method Investments

In the second quarter of 2016, the Partnership purchased a 15% equity interest in Stonewall, which operates the 67-mile Stonewall pipeline on which Antero Resources is an anchor shipper.

On February 6, 2017, we formed the Joint Venture to develop processing and fractionation assets in Appalachia with MarkWest, a wholly owned subsidiary of MPLX, LP. The Partnership and MarkWest each own a 50% equity interest in the Joint Venture and MarkWest operates the Joint Venture assets, which consist of processing plants in West Virginia, and a one-third interest in a MarkWest fractionator in Ohio.

The Partnership’s net income includes its proportionate share of the net income of the Joint Venture and Stonewall. When the Partnership records its proportionate share of net income, it increases equity income in the unaudited condensed consolidated statements of operations and comprehensive income and the carrying value of that investment on its balance sheet. When distributions on the Partnership’s proportionate share of net income are received, they are recorded as reductions to the carrying value of the investment on the balance sheet and are classified as cash inflows from operating activities in accordance with the nature of the distribution approach under ASU No. 2016-15. The Partnership uses the equity method of accounting to account for its investments in Stonewall and the Joint Venture because it exercises significant influence, but not control, over the entities. The Partnership’s judgment regarding the level of influence over its equity investments includes considering key factors such as its ownership interest, representation on the board of directors and participation in policy-making decisions of Stonewall and the Joint Venture.

The following table is a reconciliation of our investments in these unconsolidated affiliates (in thousands):


			MarkWest	Total Investment in
		Stonewall	Joint Venture	Unconsolidated Affiliates
Balance at December 31, 2017	$	67,128	236,174	303,302
Additional investments		—	91,419	91,419
Equity in net income of unconsolidated affiliates		8,346	19,486	27,832
Distributions from unconsolidated affiliates		(7,515)	(22,145)	(29,660)
Balance at September 30, 2018	$	67,959	324,934	392,893