This might not be the answer you are looking for, but based on previous experience with index options I can tell you that it was never uncommon for the spreads to widen during times of increased volatility. Obviously with a VIX as low as it is now, most people would not think that there is much volatility in the market, nevertheless we had a noticeable short term spike in volatility over the past week or so and some "faster" market conditions during that time as well. Back in 2000, when I traded the OEX more actively, the spreads would widen a bit even though they were mainly dime wide markets and very liquid three years ago. My assumption is that they need to widen their markets to hit their hedges in the ES/SP and if that market is moving faster than usual, then the customer is the one who takes on the extra risk in the form of a higher vig.
Also, another consideration is the fact that with implied volatility as low as it is, there is alot of fear in the market about a sudden, sharp and permanent increase in volatility and the event risk last week was enormous. Remember, it was this week in 1997, after a rather benign October expiration, that the great black swan event occurred on 10/27/97 when the indicies dropped like a rock and Victor Neiderhoffer was liquidated, only to see the indicies return to former highs by mid-November.
Also, another consideration is the fact that with implied volatility as low as it is, there is alot of fear in the market about a sudden, sharp and permanent increase in volatility and the event risk last week was enormous. Remember, it was this week in 1997, after a rather benign October expiration, that the great black swan event occurred on 10/27/97 when the indicies dropped like a rock and Victor Neiderhoffer was liquidated, only to see the indicies return to former highs by mid-November.
Quote from resinate:
I do have one concrete question amid this discussion with and about THEY.
The primary MM's auto-quoted b/o spread has gone from 1.00 to 1.20 in 5-10 $ spx options over the last week or so. Like I said above, until very recently and other than x week, it was pretty consistently 100$.
Was there a rule change expanding the maximum allowable spread by 20c OR is it a change in the person or behavior of the primary MM?

