The DIA art collection is valued in billions of dollars, up to $8.5 billion according to a 2014 estimate. After city's bankruptcy filing July 18, 2013, creditors targeted a part of the museum's collection that had been paid for with city funds as a potential source of revenue. State-appointed emergency manager Kevin Orr hired Christie's Auction House to appraise the collection. After months of determining the fair market value of the portion of the art that was purchased with city funds, Christie's released a report December 19, 2013, saying that the collection of nearly 2,800 pieces of the then city-owned artwork, was worth $454 million to $867 million, with one masterpiece by Van Gogh worth up to $150 million. To prevent possible sale of the works, museum proponents developed what has been named the "grand bargain". Under the plan, which was eventually approved, the museum would raise $100 million for its portion, nine private foundations pledged $330 million, and the state of Michigan would contribute $350 million for a total of $820 million in order to guarantee municipal workers' pensions. In return, the city of Detroit would transfer its portion of the collection and the building to the non-profit entity that already operates the museum. This plan was challenged by other creditors, who claimed that it treated them unfairly and requested to conduct their own appraisal of the museum collection. Some creditors came forward with offers from other parties to buy the artworks for sums higher than Christie's appraisal. On May 13, 2014, Detroit emergency manager Kevyn Orr asked Detroit automakers to add $195 million to make the grand bargain stronger. The eventual settlement did not require the DIA to sell any art.