Their petition for the immediate liquidation of his assets was converted by the judge into a 'Chapter 11' proceeding which means, under US bankruptcy law, that an administrator will be appointed to take over Mr McNall's businesses and pay the creditors if possible.
The international coin market will be shaken by this development in Mr McNall's affairs - which appears to signal the disappearance of the world's biggest buyer.
Mr McNall has always seemed a flamboyant figure in the small, scholarly world of antique coin dealing. He began collecting as a schoolboy and levered himself into the big time by attracting millionaire clients. He formed a spectacular collection for the movie mogul Sy Weintraub, then negotiated its sale to Bunker Hunt, who, with his brother Herbert, inherited the largest oil fortune in the US. They lost the lot by trying to corner the world silver market, ending up bankrupt.
In their heyday, McNall sold the brothers coins and antiquities worth about dollars 50m which had to be dispersed by Sotheby's in 1990 on behalf of the Hunts' creditors for rock bottom prices. A trust that is liquidating Herbert Hunt's assets joined the three banks suing McNall last week. The trust is seeking repayment of the dollars 915,000 Herbert Hunt paid in the early 1980s for an allegedly antique bust that turned out to be some 30 years old. Mr McNall had agreed to pay the money back but still owes about dollars 750,000.
In 1986, Mr McNall helped Merrill Lynch launch the dollars 7.3m Athena I coin investment fund, which proved so successful that the dollars 25.1m Athena II was lauched two years later. The funds bought a series of a huge coin hoards found illicitly around the Mediterranean in the 1980s.
The recession in the coin market led Merrill Lynch, on Mr McNall's advice, to start dispersing the Athena collections at a loss last year.
Mr McNall invested the fortune he had made in the coin business in film production and racehorses. Last year he still had about 200 horses.
The French-owned Credit Lyonnais Bank Nederland is Mr McNall's biggest creditor, claiming to have lent dollars 121m to his enterprises.