BOSTON, Oct 18 (Reuters) - The McKnight Foundation on Monday said holdings in its $3 billion portfolio would produce net zero greenhouse gas emissions by 2050, becoming the largest private U.S. foundation to lay out such a goal. Officials of the Minnesota-based foundation said it would continue cutting heavy emitters from its portfolio while making new investment in fields like electric vehicles or solar power, although the foundation is avoiding the stricter divestment path other institutions recently set for their fossil fuel holdings. Elizabeth McGeveran, the foundation’s director of investments, said the move is meant to pressure external fund managers and companies to provide more ways to cut carbon emissions. “We need new and better data, more transparency and more options to get to net zero,” McGeveran said. Net zero refers to a balance between emissions produced and those taken out of the atmosphere through technologies like carbon capture. The move puts the foundation in line with similar declarations from bigger U.S. investors including BlackRock Inc and Vanguard Group Inc that have made pledges to achieve net-zero portfolio holdings by 2050. Other institutional investors including Harvard University, the MacArthur Foundation and Maine state officials have vowed to cut their holdings in fossil fuel companies in response to climate change concerns. McGeveran said the McKnight Foundation had already reduced its exposure to fossil fuels as it shifted to focus on so-called “impact investments” meant to develop things like affordable housing and improved soil for farming. The foundation would still consider owning fossil fuel companies involved in energy-transition projects, she said, although likely they would eventually drop out of the portfolio. “In the short term we’ll still have exposure, in the long-term I expect we won’t,” she said. Reporting by Ross Kerber; editing by Diane Craft Our Standards: The Thomson Reuters Trust Principles.