MELBOURNE， Oct. 14 (Xinhua) -- An Australian academic's "accidental" discovery of global gold price collusion has triggered a U.S. trial of four of the world's biggest banks.

Barclays， the Bank of Nova Scotia， HSBC and Societe Generale will face a U.S. court after investors in the banks sued them for up to 750 million U.S. dollars each over allegations that the banks rigged the price of gold at the expense of investors for a decade.

The allegations came after Andrew Caminschi， an Associate Professor at the University of Western Australia (UWA)， exposed the scandal during a study of tens of millions of gold transactions in the last 18 months for a research project.

"It was a needle in the haystack-type stuff，" Caminschi told News Limited on Friday. "But once we found it， it was pretty damning."

Caminschi， who will act as an expert consultant during the trail in New York， said he never expected his obscure PhD thesis would lead to a change in the ancient gold-pricing system.

"I never thought it would get to this，" he said. "I didn't go out cartel-busting or bank-bashing -- it was more like the data was just yelling at me."

The accounting and finance professor discovered manipulation during twice-daily meetings by banks in London that determined the gold price.

An analysis of 14 years of gold-trading data found that during the meetings， before the benchmark price of gold was established， trading volumes in gold derivatives rose substantially.

The discovery suggested that the banks were trading on， and profiting from information that was not available to the wider market.

Caminschi said his supervisor was shocked when he presented his findings and explained the potential implications.

A fifth bank， Germany's Deutsche Bank， was also implicated in Caminschi's findings but settled out of court in April and has agreed to assist the plaintiffs in their case against the other four banks.