In 2011, the Andy Warhol Foundation for the Visual Arts dissolved its controversial authentication board after a string of legal challenges. Now the equivalent foundations for both Keith Haring and Jean-Michel Basquiat have cut their ties with the art market and will no longer authenticate works.

The Haring Foundation announced it would disband its authentication board and redirect the funds toward its education and HIV/AIDS-related programmes. The Foundation will honour requests for review received before September 1, 2012 but not requests submitted thereafter.

It is "exploring the development" of a catalogue raisonné for the artist. The Authentication Committee representing the estate of Basquiat also disbands this month. It was announced earlier this year that the Committee, the recipient of over 2000 works of art for consideration during its 18-year existence, would no longer accept applications for approval after September.

As reported last week, the Warhol Foundation, much criticised after spending $7m alone fighting a lawsuit brought by Joe Simon-Whelan, owner of the 'double denied' Warhol self-portrait, who accused the board of attempting to monopolise demand for the artist's work, has struck an exclusive deal with Christie's to sell its enormous holdings of works from the artist's estate.