Short wings will not get you far. Long wings will fly you when the winds pick up.
Vol traders are well aware of the volatility skew. Prices on far out-of-the-money options are often "over-priced" according to the traditional Black-Scholes model. The B-S model assumes constant volatility, so the idea of a vol surface is kinda backwards anyway. Assuming market prices, you can back out the B-S vol. B-S vol is usually higher on far out-of-the-money stuff.
The good academic might say these are over-priced and ought to be sold. Then kurtosis comes into play. Fat-tails make selling the wings quite dangerous. But a good simulation model that takes into account the fat-tails might still tell you the options are over-priced. Do you sell them?
Here's the trader's perspective. Being long the wings means once in a very long while you'll make a shit-load of money. Being short the wings means once in a very long while you'll be out of a job. Even if most of the time you're making a little bit of money by selling the wings, is it really worth betting your career? Sorta. . . not really. That being said, selling options is not necessarily a bad thing. In fact, selling options is quite profitable. It's the selling options for no real profit that seems dangerous.
A lot of non-trading circumstances are analogous. Don't be an ass-hole to random people you meet, you never know which might be your next boss--or be packing a gun and have rage issues (don't get me wrong, being an ass-hole in general is fine if you can pull it off. Just don't be an ass-hole randomly). Don't play hookey from work. Don't have unsafe sex with a hooker. Don't take chances unless you're getting the just reward for it.
Thursday, August 9, 2007
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