The SPDR Gold Shares (NYSEArca: GLD), the world’s largest gold bullion ETF, fell more than 1.5 percent today on news that George Soros cut his position in the fund by a whopping 55 percent to 600,000 shares during the fourth quarter of 2012, according to a quarterly regulatory filing.

Gold was last trading just above $1,607 after ending the session yesterday at $1,634.75. It hit a low just below $1,600 early in Friday’s session. Viewing gold prices through the lens of the ETF, GLD closed yesterday at $158.35, and was last trading at $155.41 after hitting a low of $154.57.

Soros Fund Management holdings of GLD have ranged from 42,800 shares in 2011 to as much as 6.2 million shares in 2009.

However, Soros, while certainly well regarded, isn’t known for being a steadfast gold bull. In September 2010, the billionaire investor said the yellow metal was “the ultimate asset bubble”; at the time, prices were trading at a mere $1,275.

A fellow billionaire, John Paulson, is known for having more conviction in the gold bull market. His closely watched holdings of the SPDR Gold Trust remained unchanged during the fourth quarter at 21.8 million shares.

Nevertheless, today’s plunge in gold prices below $1,600 may have little to do with either of these billionaire investors, which Soros and Paulson detailed in so-called 13-F documents each filed with the Securities and Exchange Commission on Thursday.

13F filings, required of institutional money managers who have at least $100 million in qualified assets under management, must be filed with the SEC 45 days after the end of each quarter.