Scott Nielsen is the director of advocacy at the left-of-center Arabella Advisors investment firm. In this role, he helps Arabella’s clients use their financial resources to accomplish left-of-center political goals. Arabella manages the pass-through funding entities New Venture Fund for advocacy groups registered as charities and the Sixteen Thirty Fund for advocacy groups registered as “social welfare” organizations; due to that connection, Nielsen has been involved in the activities of those organizations. Critics charge that both NVF and Sixteen Thirty Fund are “dark money” operations which obscure the involvement of prominent people in political advocacy.
Nielsen has called for philanthropic funders to use issue advocacy as a means to obtain the political clout necessary to enact left-of-center policies aligning with their respective left-leaning philanthropic missions. Nielsen touts or has been involved with the management of numerous Arabella initiatives that seek to use donor funds to push for left-of-center public policies, such as the Safety Net Defense Fund, which seeks to preserve expansive government low-income social welfare programs.
Before joining Arabella, Nielsen ran his own consulting firm, which helped donors to create and implement their left-of-center grantmaking programs.  Nielsen’s firm’s clients included George Soros’ Open Society Foundations, the Democracy Alliance, the Carnegie Corporation of New York, the W.K. Kellogg Foundation, the Funders Committee for Civic Participation’s (FCCP) State Infrastructure Fund,  the Ford Foundation, and the McKay Foundation. 
Also see Arabella Advisors (For-Profit)
Since December 2015, Scott Nielsen has served as first managing director of advocacy for Arabella Advisors. In this role he develops strategies for using Arabella’s resources to push for the political goals of the firm’s liberal clients. Nielsen specifically focuses on civic engagement, issue advocacy, public policy, infrastructure development, and field building.
In a 2016, Nielsen argued that strategic philanthropy requires funders to engage in political advocacy. Nielsen bemoaned the fact that contemporary “ideological polarization” and “fiscal restrictions” had turned liberal government spending programs into partisan issues. From this, Nielsen concluded that funders must use issue advocacy to build the public and political capital necessary to “achieve influence at multiple levels” that can lead to the enactment of funders’ preferred left-of-center social policy changes. 
Nielsen listed a number of specific advocacy tools that funders could use to achieve these policy goals. These tools included; lobbying, issue campaigns, litigation, polling and public opinion research, strategic communications, policy development and analysis, and issue research.
Nielsen also noted that Arabella Advisors managed several different nonprofits dedicated toward helping client-donors pool their money to seek enactment of specific liberal social issues. As an example, Nielsen touted the Arabella-managed Sixteen Thirty Fund, which had previously hosted advocacy and lobbying initiatives that helped to create government-funded healthcare policies, expansions in government social program spending, and liberal technology regulations.
Safety Net Defense Fund
As Arabella Advisors’ managing director of policy, Nielsen was listed as the main point of contact for the Arabella Advisors project Safety Net Defense Fund (SNDF).
The SNDF campaign is run under Arabella Advisors’ Sixteen Thirty Fund, a 501(c)(4) advocacy group, and in partnership with Arabella’s New Venture Fund, a 501(c)(3) left-wing funder and fiscal sponsor group. The campaign launched in December 2016 with an estimated $8 million budget and seeks to build the political power and influence necessary preserve expansive government low-income social welfare programs such as Medicaid, food stamps, and other Federal income supplement programs.
The SNDF campaign has worked closely with a number of left-of-center organizations including Community Catalyst, Georgetown Center for Children and Families, Families USA, HCAN Education Fund, Protect Our Care on Medicaid, the Food Research and Action Center, and Feeding America on SNAP.
The campaign also partnered with left-of-center groups like the Center for American Progress and left-leaning companies such as Spitfire Strategies and BerlinRosen to generate earned media, and communications content.
Nielsen also serves as a managing director of the Arabella-run Hopewell Fund. The Hopewell Fund has run a number of left-wing domestic and international projects. One such Hopewell Fund project explored the viability of providing cash handouts through state and local “basic income” campaigns.
Alexander Nielsen Consulting
Scott Nielsen served as a principal and co-founder at Alexander Nielsen Consulting from September 1999 through November 2015. 
Alexander Nielsen clients included a number of major left-of-center foundations including the Open Society Foundations, the Democracy Alliance, the Carnegie Corporation of New York, the W.K. Kellogg Foundation, the Funders Committee for Civic Participation’s (FCCP) State Infrastructure Fund, the Ford Foundation, and the McKay Foundation. Other left-of-center clients included Minnesota Public Radio, the Robert Wood Johnson Foundation, California Endowment, American Values Project, State Voices, MacArthur Foundation, Atlantic Philanthropies, and the Marguerite Casey Foundation.
While a principal at Alexander Nielsen, Scott Nielsen co-authored a 2009 report published by the Foundation Center and sponsored by the Ford Foundation detailing left-wing social justice grantmaking trends. The report called for funders to build a “social justice infrastructure,” support ostensibly “nonpartisan” political organizations that build the political leverage and expertise necessary to address larger liberal social justice issues, and to “support identity-based philanthropies.”
In 2007, Nielsen gave a presentation at a State Strategies Fund meeting at which he touted “the early 90’s as the gold standard” for how moving resources to build state capacity could work. According to Nielsen, during this era grantees and funders created an infrastructure to discuss strategic needs to carry out left-of-center activities. He then provided an example of how various left-of-center funders such as “Schumann, Joyce, Carnegie, Proteus, and OSI [the Open Society Institute, a George Soros philanthropy]” would pay for their respective advocacy pieces.
Nielsen also co-authored a 2004 article that called for philanthropists to support the expansion of so-called “focus funds,” which were philanthropies tied together by a shared communal background such as funds focused on minority groups, women and gay/lesbian communities and which seek to invest their money in ways that address the social issues that those groups face.
From 1986 through 1999 Nielsen worked “as a program officer at the John D. and Catherine T. MacArthur Foundation, including seven years in the MacArthur Fellows Program.” In this role, Nielsen “designed, managed, and assessed major foundation initiatives” aimed at liberal campaign finance, international human rights, economic globalization, and racial/ethnic issues. 
Nielsen has served as an advisor or board member to a number of left-leaning organizations including State Voices, Boston Review, Faith in Public Life, Proteus Fund, New America Research Network, and the American Independent News Network.
In 2018, Nielsen is a member of the leadership team for the Funders Committee for Civic Participation’s Funders Census Initiative 2020.