An error by the Netherlands' banking watchdog caused the details of hundreds of previously private short selling trades by international hedge funds, including those of George Soros and also the positions of Renaissance Technologies' enigmatic Medallion fund, to briefly go on public on Tuesday evening.

According to a report by Financial Times, Dutch markets regulator the AFM published the details of hundreds of hedge fund short trades going back to 2012. . An AFM spokesperson said there was a mistake and the regulator moved quickly to correct it.

However, the details published briefly showed that Soros' family office to have bet against the Dutch bank ING, taking a short position of 0.3% in the lender in June 2016 before being scaled back a month later, the Financial Times reported.

"On the afternoon of Tuesday 24 January, after the close of the market, the AFM inadvertently published a list on its website that included net short positions of less than 0.5% instead of publishing the daily list of net short positions of 0.5% and higher," the AFM statement published on its official website said.

"The AFM corrected this mistake and posted the correct list of net short positions of 0.5% and higher on the morning of Wednesday, 25 January. We regret this error."

The details also showed that bets by the computer-driven Medallion fund operated by the US hedge fund Renaissance Technologies, a company that has long been closed to outside investors and only manages the fortunes of the Renaissance partners. .

The list revealed that the Medallion fund has taken out several bets against small Amsterdam-listed companies since 2012. According to the Financial Times, hose that are still outstanding include the specialty metals company Advanced Metallurgical Group, Ordina, an IT company with a market value of under €200m, and the closed-ended real estate company Wereldhave N.V.