A US federal judge has ruled that two banks and two auditors will not need to face charges over the collapse of Italian dairy firm Parmalat in 2003.
US district judge Lewis Kaplan said much or all of the alleged improper conduct took place outside of the US.
Citigroup, Bank of America, Deloitte Touche Tohmatsu and Grant Thornton will now not need to face charges, he said.
Parmalat was Europe’s biggest bankruptcy, and investors have taken legal action to get their money back.
Earlier this week, an Italian judge ruled that Parmalat’s founder, Calisto Tanzi, and other former executives should face trial.
Parmalat collapsed with a 14bn-euro ($18.6bn; £9.4bn) hole in its accounts and a number of international firms and banks were caught up in the legal storm that followed.
Judge Kaplan ruled that the charges against Citigroup, Bank of America, Deloitte Touche Tohmatsu and Grant Thornton were not covered by US securities law.
“Where the United States activities are merely preparatory or take the form of culpable nonfeasance and are relatively small in comparison to those abroad, the securities laws do not apply,” he said.
However, he added that the ruling would not block US buyers of Parmalat securities from going through US courts.
A lawyer for the investors trying to recoup their losses said: “Obviously, we’re disappointed with the judge’s ruling.”
Mark Willis of Cohen, Milstein, Hausfeld & Toll said the investors, many of whom were European, may launch an appeal or turn to European courts.