The Yellow Chair Foundation is a private grantmaking foundation based in San Francisco, California. It was created by Yahoo co-founder David Filo and his wife Angela.
The organization supports environmentalist campaigns, most prominently funding among other things the Sierra Club’s “Beyond Coal” campaign to shut down every coal-fired power plant in the United States alongside former New York City Mayor Mike Bloomberg’s Bloomberg Philanthropies.  In addition, the organization makes grants in the media space and the civil liberties area. It also funds gender equality programs and educational programs.
The Yellow Chair Foundation is the foundation of Yahoo co-founder David Filo, whom Forbes reported was worth an estimated $4.3 billion as of September 2019. 
The day-to-day operations of the foundation are reportedly run by David’s wife Angela Filo. Angela has an undergraduate degree from Sanford in human biology and a master’s in journalism from the University of California Berkeley. She has taught journalism and photography at Eastside College Preparatory School and sits on the board of trustees of Stanford University. 
The foundation’s office is managed by Pacific Foundation Services, a vendor that manages numerous foundations.  In 2017, Yellow Chair Foundation reported paying PFS $353,383 for consulting services. 
The foundation was established in 2000 by the Filos. The foundation does not have a website and does not have any trustees other than David and Angela Filo. 
The foundation is known for its environmentalist giving; it is a supporter of the Sierra Club’s “Beyond Coal” campaign which aims to close every coal-fired power plant in the United States. It is also a supporter of the Energy Foundation and the Environmental Defense Fund. Before donating to the Sierra Club’s campaign, the EDF was the main recipient of Yellow Chair Foundation environmental giving. 
The foundation played a role in the EDF’s campaign to reform the oversight of chemicals in products. In 2016, the foundation funded the EDF’s campaign to successfully pass the Frank R. Lautenberg Chemical Safety for the 21st Century Act which amended the Toxic Substances Control Act. The law established mandatory requirements for the EPA to evaluate chemicals and provided for increased public transparency for chemical information. 
The foundation also funds education programs. Many of these programs are targeted at getting first generation students into and through college. It also funds programs to help train and equip public school teachers. 
The foundation also funds journalistic programs. It is a funder of the Student Press Law Center which advocates for the First Amendment rights of students. It also funds the left-leaning investigative journalism website ProPublica; ProPublica’s 2017 tax returns reported receiving $1,000,000 in contributions from Yellow Chair Foundation. 
The foundation is also a substantial funder of the American Civil Liberties Union and its associated groups. “Advocacy for criminal justice, reproductive, voting, privacy, and other rights make the work of the ACLU so compelling and their watchdog role so important,” Angela Filo told a magazine in 2017.  In 2017, Yellow Chair Foundation reported contributing $3.9 million to the ACLU’s charitable arm, the ACLU Foundation. 
According to the Yellow Chair Foundation’s 2017 tax returns, the foundation had revenue of $85.8 million. It spent $13.9 million of which $11 million was outgoing grants. It had $314.4 million in assets at the end of the year.