The gold bloodbath that hit the market over the past two trading sessions has definitely caused a dent in the portfolio of billionaire hedge fund managers. John Paulson and David Einhorn suffered combined losses of more than $640 million since Friday, according to their latest SEC filings, with the bulk concentrated in the former?s massive position in the SPDR Gold ETF. Einhorn’s Greenlight took a big hit on its holdings of the gold miners ETF.