A prominent S&P 500 short seller, known as "Silver Iron Head Air Force" (0x61cee), has initiated a significant short position on NVIDIA. The trader is shorting 66,640 units of the NVIDIA mapping contract (xyz:NVDA) at 10x leverage, with an average entry price of $196.37. The total position value stands at $13.19 million, and the trader is currently facing an unrealized loss of $108,000.