The Swiss art historian facing fraud charges after he acted as an agent in the sale of a fake Mark Rothko painting by the now defunct Knoedler Gallery in New York has settled with the buyer out of court.

Casino magnate Frank Fertitta who purchased the work from the once-prestigious Knoedler art dealership in 2008 accused Oliver Wick, a Rothko expert, of misleading him about the forgery. The terms of the settlement filed in Manhattan federal court on 11 April remain unknown.

Wick, a former curator at the Fondation Beyeler in Basel, was a defendant in the lawsuit filed by Fertitta against Knoedler in April 2014. It was the eighth of ten lawsuits brought against the gallery and its former director, Ann Freedman, for selling over 30 works of Abstract Expressionist art forged in a garage in Queens and is the seventh to have settled out of court.

The art historian wrote to private dealership, Eykyn Maclean, in April 2008 to verify the painting’s authenticity. “I confirm that this work has been submitted to the [Rothko catalogue raisonné] team, all is perfectly fine, otherwise I would not want to be involved with it. For this I stand with my name as a Rothko scholar”, Wick stated in an email. Eykyn Maclean contacted Fertitta who bought the painting for US$7.2 million (£5.8 million) on the strength of Wick’s assurance.

The billionaire owner of the Ultimate Fighting Championship resold the counterfeit work to an unidentified buyer in 2011. It was only after reading an article in The Art Newspaper in 2013 that identified those who had purchased fake works from Knoedler that he became aware of the forgery scandal, which first broke in 2011. Realising the painting was fake, Fertitta reimbursed the buyer US$8.5 million (£6.8 million) and sued the gallery with whom he reached a settlement on 14 October 2016.

For his role as an agent in the sale of the work Wick received a US$300,000 (£240,293) consulting fee from Knoedler as well as a US$150,000 (£120,146) “introductory commission” paid by Fertitta. Following the original sale, the art historian attempted to sell another alleged Rothko painting to Fertitta, which he claimed was a “perfect match” and looked like it had been painted “within a week” of the first work.