只有“波形”发生变化，才能携带有效的信息,只有波包的群速度可代表信号传播的速度:The SPX keeps having a t

来源: marketreflections 于 2011-08-16 19:59:16 [档案] [博客] [旧帖] [给我悄悄话] 本文已被阅读：次 (9188 bytes)

回答: 尤亦庄 phymath01 波和振子是不同的能量密度和能量是不同的由 marketreflections 于 2011-08-14 11:21:13

The VIX Must Fall and is about to Officially Be Overpriced

Posted by msebastian on Tue, 08/16/2011 - 7:13pm

What does an overpriced VIX really mean? If one looks at historical volatility relative to implied volatility the VIX is almost always to high, traditionally it’s considered 2-3% over priced. This is because in order for the VIX to be fairly priced it would have to move more than 2% (actually 32.85/ (sqrt 252)). Right now though the SPX seems to be slowing down, not speeding up:

The SPX keeps having a tighter and tighter range today moving more like 1%, which would put the VIX closer to 16% than 32%. This is part of the reason that we are seeing the VIX have lower highs and lower lows (a sign it is overpriced):

Today, when the SPX was down almost as much today as it was up yesterday the VIX was only picking up about half of what it gave up yesterday. You'll recall I spoke about the VIX ramping up on CNBC (look at our front page to watch); if they had me back on today (I'll be on sometime soon, just not today) I would talk about how I see the VIX ramping back down. Do I think there is still a decent chance for a trip to 40...yes, but I do not think it’s a sure thing anymore? No I do not.

Another thing to notice is that this is the first day where the VIX and the volatility of VIX options have moved in opposite directions. Today IV of VIX options was down not up, skew flattened as well. This is yet another sign that expectations of a major pop in IV is considered increasingly less likely.

This presents us with many opportunities in VIX options, VIX etn's and SPX. I am at this point, bullish in the short term. I would point out that there are some very juicy IV's for those with the guts to sell premium here, especially relative to the movement. That said, make sure to insure. VIX IV is high, but with steepened skew, call spreads to not seem that expensive. The same holds true in SPX, if an outright put is too much, what about a put spread?

For those that want to trade 'income' spreads, take a look at condors, they seem to make the most sense.

graphs from LiveVolPro