Arabella Philanthropic Investment Advisors
http://www.arabellaadvisors.com
Arabella Advisors is a philanthropy services firm dedicated to supporting the work of philanthropists worldwide. Arabella offers strategic counsel based in business principles to help their clients improve the effectiveness and efficiency of their giving. Their website details their comprehensive approach to philanthropic advising, and includes case studies of a broad range of client organizations.

The Bridgespan Group
http://www.bridgespangroup.org
The Bridgespan Group is a not-for-profit strategic consulting firm focused exclusively on the nonprofit and philanthropic sector. Bridgespan provides strategy consulting, executive search, and philanthropy advising to help nonprofit organizations and philanthropists develop and implement strategies with the potential to achieve significant results.

The Endeavor Group
http://www.theendeavorgroup.com
The Endeavor Group represents the philanthropic and advocacy interests of a select group of entrepreneurial, high net-worth individuals. Endeavor offers a cross-disciplinary suite of advisory services that includes legal, regulatory, financial, communications and brand management components. The firm’s clients are deeply engaged in their own philanthropic initiatives, and Endeavor works shoulder-to-shoulder to help these clients achieve high returns on their philanthropic investments. Endeavor’s website highlights a cross-section of the firm’s clients, and provides detailed case studies of its work.

FSG
http://www.fsg-impact.org
FSG Social Impact Advisors is a nonprofit 501(c)(3) organization dedicated to accelerating social progress by advancing the practice of philanthropy and corporate social responsibility thorough advice, ideas, and action.

Rockefeller Philanthropy Advisors
http://www.rockpa.org
Rockefeller Philanthropy Advisors helps donors create thoughtful, effective philanthropy throughout the world. Rockefeller Philanthropy Advisors provides research and counsel on charitable giving, develops philanthropy programs, and offers complete program, administrative and management services for foundations and trusts. It also operates a charitable gift fund (The Philanthropic Collaborative) through which clients can make gifts inside and outside the United States, participate in funding consortia, and operate nonprofit initiatives. Rockefeller Philanthropy Advisors currently serves more than 160 clients in facilitating over $200 million in annual gifts/grants to more than 60 countries.

The Philanthropic Initiative, Inc.
http://www.tpi.org
The Philanthropic Initiative, Inc. (TPI) is a nonprofit advisory team that designs, carries out and evaluates philanthropic programs for individual donors, families, foundations, and corporations. Since it was founded in 1989, TPI's goal has been to help clients to invest in their own values, communities and societies for maximum impact.