GreatPig
Pigs In Space
- Joined
- 9 July 2004
- Posts
- 2,368
- Reactions
- 14
Hello Gp,GreatPig said:A few questions, as I'm trying to get more of an understanding of this topic.
1. What method do you use to work out option values? I don't have the Hoadley Excel thing (although have tried the free calculators on the Website), but I gather it includes the Black-Scholes, Binomial, and one or two other formula. If you primarily just use the Black-Scholes method, how do you allow for dividends and the possibility of early exercise on American-style options, or do you find they don't make much difference?
2. How do you know if this formula is giving valid results? It seems to me that there are essentially two unknowns in the formula: option value and IV, and that by fiddling with IV you can always get the option value to match the current market price. Consequently, if the underlying price changes and when you plug that into the formula it gives a value other than the current market price, do you assume that's just because the IV must have changed or that possibly the model the formula is based on is not accurate? The texts I've read all note that prices don't always match the lognormal distribution assumed by Black-Scholes, and that there can be different degrees of skew and kurtosis (that I can plot in AmiBroker), which implies that the formula won't always give accurate results. But does it really matter for practical purposes?
3. Is it possible to get historic IV information for ASX stocks? I've seen some of you talking about IV plots, as opposed to simple SV plots which I can do in AmiBroker, and wonder where you get the data from - especially for the Australian market. And is the IV data for the share or the derivative, as I've noticed different derivatives on the same share can show different IV values (although generally not much different)?
4. When calculating IV, I gather the general method is to work backwards using the current market price as an input. How then do the MMs come up with a figure when they may be the whole market for a particular warrant (and presumably option) for much of the time? In other words, when I look at a warrant and see a particular bid/offer spread from an MM, and no other bids or offers (and quite possibly no trades ever for that instrument), how are the MMs coming up with an IV value so as to set a price? When I compare most back-calculated IV values with current SV values of the underlying in AmiBroker, they are invariably higher - no matter what SV time frame I use. What other information might an MM be using to determine a higher IV?
Thanks.
GP
GreatPig said:A few questions, as I'm trying to get more of an understanding of this topic.
1. What method do you use to work out option values? I don't have the Hoadley Excel thing (although have tried the free calculators on the Website), but I gather it includes the Black-Scholes, Binomial, and one or two other formula. If you primarily just use the Black-Scholes method, how do you allow for dividends and the possibility of early exercise on American-style options, or do you find they don't make much difference?
Mags done a great job with this one already
2. How do you know if this formula is giving valid results? It seems to me that there are essentially two unknowns in the formula: option value and IV, and that by fiddling with IV you can always get the option value to match the current market price. Consequently, if the underlying price changes and when you plug that into the formula it gives a value other than the current market price, do you assume that's just because the IV must have changed or that possibly the model the formula is based on is not accurate? The texts I've read all note that prices don't always match the lognormal distribution assumed by Black-Scholes, and that there can be different degrees of skew and kurtosis (that I can plot in AmiBroker), which implies that the formula won't always give accurate results. But does it really matter for practical purposes?
The thing to remember is that the option pricing models give "theoretical" outputs. Ultimately, because options are traded by the open auction process of a public exchange, they are beholden to market forces. In other words, the option will only trade at a price that is acceptable to both parties. This of course is s dynamic process and can vary from minute to minute, strike to strike, expiry to expiry. Black-Scholes, Cox Ross & Rubinstein et al have merely devised elegant mathematical formulas to explain, quantify and standardize risk aspects of options and hence there pricing (some would argue that they are not elegant solutions at all, but I am personally in awe of the job they've done)
The models are the only thing we have to work with, and for the most part they do a great job. But a model is just....a model.
3. Is it possible to get historic IV information for ASX stocks? I've seen some of you talking about IV plots, as opposed to simple SV plots which I can do in AmiBroker, and wonder where you get the data from - especially for the Australian market. And is the IV data for the share or the derivative, as I've noticed different derivatives on the same share can show different IV values (although generally not much different)?
Margaret reports IV charts are available on Webiress via Morrisons, probably also on other brokers with the webiress platform.
www.premiumdata.net also has historical IV data in metastock format, which can be plotted in Amibroker. If you go this route, I have done some work with these that I can help you with as far as plotting them etc. But I suspect someone that can devise a trendline formula is quite capable enough
Generally, IV charts will plot a mean IV value. But IV can and will vary beteen strikes and expiries, hence "volatility skew"
4. When calculating IV, I gather the general method is to work backwards using the current market price as an input. How then do the MMs come up with a figure when they may be the whole market for a particular warrant (and presumably option) for much of the time? In other words, when I look at a warrant and see a particular bid/offer spread from an MM, and no other bids or offers (and quite possibly no trades ever for that instrument), how are the MMs coming up with an IV value so as to set a price? When I compare most back-calculated IV values with current SV values of the underlying in AmiBroker, they are invariably higher - no matter what SV time frame I use. What other information might an MM be using to determine a higher IV?
IV can be an input or an output. For the trader it is an output that we reverse engineer from price (thank god for software) For the market maker, sans any buying or selling pressure, it is an input used to calculate price/spread and is based on their volatility projections *plus* a consideration for any slippage in hedging. This is seen as a widened spread at the open, close of all series, and all the time in illiquid series.
When IV is consistently higher than SV, that is what we call chronic overvaluation. It exists in certain series such as index options, NWS etc. I like chronic overvaluation as it provides an edge, which i have written much about previously
Thanks.
GP
Wouldn't though the bulk of the market be using these same models to value their options? Otherwise, how would they be coming up with a figure for the value? How did they do it before these models were created?Ultimately, because options are traded by the open auction process of a public exchange, they are beholden to market forces.
GreatPig said:Thanks Magdoran & Wayne. Great replies.
Regarding one point of yours Wayne:
Wouldn't though the bulk of the market be using these same models to value their options? Otherwise, how would they be coming up with a figure for the value? How did they do it before these models were created?
It seems to me that if most people are using these models to value their options, then that of itself would make the models fairly accurate.
Hello dubiousinfo,dubiousinfo said:Have been looking at some ZFX puts options and decided to look at warrants as well.
October $11.00 options and warrants
Option:
ZFX4A buy .56 sell .63
Warrant:
ZFXVZQ buy .56 sell .57
The warrant has a ratio of 3:1 so you need 3 warrants to cover 1 share.
They both have similar strike price and expiry dates yet the warrant looks way over priced compared to the option. So why would anyone take the warrant over the option??
What am I missing here?
Nice idea ice,ice said:dubiousinfo,
In relative terms warrants usually price 5-10% higher than the equivalent ETO's.
However in this case the apparent extreme over-valuation is a consequence of ZFX going ex-div prior to expiry (70 c on 16/10). The warrant is european style and can't be exercised before the div so consequently the matrix differs from that applied to the american style ETO.
ice
Hello Margaret,sails said:Hi Mag,
Apart from occasionally trading instalment warrants, I haven't had much other experience with warrants in general - don't have a lot of faith in the issuersThey seem to be a law unto themselves - eg this morning I had several CTW barrier warrants on my watchlist (BHP, ANZ and NAB - both puts and calls) and suddenly the quotes disappeared off the lot for approx 15 minutes I have been watching these barriers to see if they might be useful to hedge option spreads instead of using the underlying due to their delta of almost 1 - do you have any thoughts on this?
The other thing I have noticed when comparing options with normal trading warrants is the warrants have a set ratio of shares per contract. If we take an example of a 4:1 ratio, I have generally assumed that their delta will never move much away from .25 except for volatility fluctuations, or in other words, they lack the gamma component of options - is this correct?
If that is so, then options would have to be more attractive for long premium as the delta will increase with movement when it's moving in our favour and decreasing when it's moving against (providing IV remains constant!). It also means the warrant MM's almost have their cake and eat it too!
Hope you had a good time in sunny Qld last week where we had near summer weather. All gone now - it's wet and windy!
Regards,
Margaret.
Hello dubiousinfo,dubiousinfo said:Magdoran
Thx for your help.
I have been right through the issuer documentation but cant find any reasons for the amount of differnce (although its certainly possible I have missed something).
I have good profits from ZFX Shares I have held for some time & intend to continue to hold, as I believe there is still upside left in the medium term. However I was considering some puts to ride out Sept/Oct as I believe some short term weakness in zinc & ZFX may be possible under certain conditions.
Was just exploring the possibilities when I came across the anomaly. I normaly use options rather than warrants for this type of thing & while my knowledge of the greeks could definatly be improved, I probably have the basics on them.
I take on board what you have said about delta, but watching them over the last few days as the price of ZFX has moved, the movement of the warrant prices seems to have been less than the options. (which I guess implies the warrant has a lower delta).
Hyperthetically, if I was to purchase both of these & just hold till expiry & assuming they finished ITM, the cost to payout ratio of the warrants would appear to be substantially lower than the options. Is this correct?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?