A significant number of options on the volatility index are expiring worthless after the index settled at 21.36 for the Dec expiration and below today’s lowest reading in the spot index, which is 21.87. VIX settled 36 percent below the levels seen at the previous expiration, when the settlement value was 33.36. The largest open interest position in the index heading into the expiration was VIX Dec 20 puts. OI is 166,600. Upside Dec 35, 40, and 45 are among the largest positions as well. The settlement of VIX, which is computed using implied volatility in the options on the SPX rather than the spot index itself, might be one factor driving the unusual behavior of the index today. The market’s “fear gauge” is down .55 points to 22.67 and falling to multi-month lows, even as the S&P 500 is down 7 points on the session.