As we previously reported, in Sun Capital, the U.S. Court of Appeals for the First Circuit held in 2013 that a private investment fund, pursuant to the so-called “investment plus” test first articulated by the Pension Benefit Guaranty Corporation (the PBGC), was engaged in a “trade or business” under the Employee Retirement Income Security Act of 1974, as amended (ERISA) and could therefore be part of a “controlled group” with one of its portfolio companies and potentially liable for the portfolio company’s underfunded pension liabilities.  The Sun Capital case was remanded to the U.S. District Court of Massachusetts for further proceedings on whether a related private investment fund that invested in the portfolio company was also engaged in a “trade or business” and whether the two funds were under “common control” with the portfolio company.  On March 28, 2016, the District Court determined that the second private investment fund was engaged in a “trade or business” and that the two funds’ co-investment in the portfolio company constituted a “partnership-in-fact” (resulting in the aggregation of their ownership interests in the portfolio company) that was also engaged in a “trade or business.” This determination resulted in both funds being treated as part of the portfolio company’s “controlled group.”