Tag Archives | time decay

The Option Greeks and the Passage of Time

In one of my live interactive meetings with Gold Members at Options for Rookies Premium, we were talking about the passage of time and whether option premium (and thus, bid/ask quotes) were adjusted smoothly with the passage of time or whether they ‘jumped’ each morning as a result of it now being ‘one day later.’ This is a typical (good) question from someone who is new to trading options.

By the way, the answer to the above question is ‘neither.’ Other bloggers, including Mark Sebastian, have discussed this point in detail (Option Pit) , but let me say that market makers have a system for marking the passage of time. My guess is that each uses a proprietary method and that everyone’s timepiece would not read the same time. In simple terms, the ticking clock speeds up as we move from Monday to Friday.

Regardless of the specific details, the people who set the markets accelerate time decay as the end of the week approaches. In other words, the theoretical clock ticks much faster on Friday than on the previous Monday. Why would market makers do this? It’s an attempt to smooth out the passage of time when taking into consideration that the markets are not open for trading on the weekends.

If the option traders used the ‘true’ Friday theoretical values for their bids and offers, when Monday morning arrived each option would (assuming an unchanged sock price) be lower than on Friday. This would be especially obvious as expiration week arrives. To discourage others from ‘dumping’ option premium of Friday and repurchasing Monday, the passage of time used to determine the value of an options is not measured in real time – at least not as weekends approach.

Whether this is a good idea (no markets are open over the weekend) or a bad idea (wars can start over a weekend) is not the point.

That discussion brought us to more questions about how time affects other greeks (in addition to theta). Does delta, gamma, vega change as time passes? The answer is yes, it does. Most of the time, beginners are not introduced to these concepts because they are not important factors on a day to day basis. There are general themes that are important (such as how does delta change as expiration nears), but the details are often overlooked. The math gets complex, but as will all math used in the options world, we have calculators to do the difficult tasks.

With that background, I believe it’s a good idea to introduce you to some of the second order greeks – with the understanding that this is basically a FYI discussion. If you want to get a deeper glimpse into the world of risk measurement when using options (the greeks), read on.

The following is from Wikipedia

Higher-order Greeks

Charm

Charm, or delta decay, measures the instantaneous rate of change of delta over the passage of time. Charm has also been called DdeltaDtime [the rate of change of delta with respect to time]. Charm can be an important Greek to measure/monitor when delta-hedging a position over the weekend. Charm is a second-order derivative of the option value, once to price and once to the passage of time. It is also the derivative of theta with respect to the price of the underlying

Practical use

The mathematical result of the formula for charm is expressed in delta/year. It is often useful to divide this by the number of days per year to arrive at the delta decay per day.

This use is fairly accurate when the time to option expiration is large. When an option nears expiration, charm itself may change quickly, rendering full day estimates inaccurate.

Color

Color, or gamma decay (or DgammaDtime) measures the rate of change of gamma over the passage of time. Color is a third-order derivative of the option value, twice to underlying asset price and once to time.

Color can be important to monitor when maintaining a gamma-hedged portfolio. It can help the trader anticipate the effectiveness of the hedge as time passes.

Practical use

The mathematical result is expressed in gamma/year. It is often useful to divide this by the number of days per year to arrive at the change in gamma per day. This use is fairly accurate when time to expiration is large. When an option nears expiration, color itself may change quickly, rendering full day estimates inaccurate.

DvegaDtime

DvegaDtime, measures the rate of change of vega with respect to the passage of time. DvegaDtime is the second derivative of the value function; once to volatility and once to time.

Practical use

It is common practice to divide the mathematical result of DvegaDtime by 100 times the number of days per year to reduce the value to the percentage change in vega per one day.

There are other 2nd and 3rd order greeks. Today’s discussion is untended to introduce you to the fact that the greeks are all sensitive to the passage of time. And as with the first order greeks with which we are familiar, an approaching expiration date can produce sharp changes in their values.

Read full story · Comments are closed

As expiration nears, how does theta behave?

Mark,

I am currently on my second round reviewing the greeks, and this time I am going into more depth. As I am putting together my notes I found references that describe time decay for both OTM and ATM positions. To my surprise, the shape of the graphs is different.

The graph that we are all accustomed to seeing shows that time decay accelerates as expiration nears. Most of the theta decay occurs in the last 30 days in which theta is increasing as the remaining time value of the option is decreasing.

Time_value_of_an_option__standard

When it comes to OTM options, according to the authors, the shape changes significantly. In the last 30 days, decay decelerates and the majority of the decay occurs before the last 30 days. This is the graph of an OTM option and its time decay.

Time_value_OTM_options_

I have been looking at various option series for both stocks and ETFs and I have not been able to confirm this.

Question.

If the above statement is true, when trading iron condors, why wouldn't you pick a timeframe for opening the position near 60 days to expiration and probably closing ~30 days before expiration? This would allow the trader to capture a larger portion of the time decay – because OTM positions make up the iron condor.

JG

***

This is a very thoughtful question and illustrates why spending time trying to understand the things we are taught is such a good idea.  Thank you.

The general view regarding time decay is correct.  Theta accelerates as expiration approaches.  However, we must recognize that some siturations are different.  Let's say that a stock is trading near 79, there's a week left prior to expiration, and the option under consideration is the 80 call.  Surely that option has time value and with that comes time decay – and the option loses value every day.  Just as you anticipate.

However, consider the call option with a 50 strike.  Unless this stock trades with an extreme volatility, the call has already lost all time value (except for a component due to interest rates) and trades with a bid that is below parity. 

Or you can look at the corresponding put (which has the same theta) and see that it doesn't trade and the bid is zero. It has already lost every penny of it's time value.  Its theta is zero.

These are the situations to which your references are referring when stating that time decay decellerates into expiration.  When options move to zero delta and 100 delta, the time decays disappears prior to expiration.

Most traders who are talking about options and their time decay, are not interested in such options (there is nothing of interest for a trader to discuss).  Thus, options such s the 80 call mentioned above (and the corresponding 80 put) have time value, accelerating time decay and an increasing positive gamma.  These options decay according to your first, or 'standard' graph.

FOTM options

There is more to the rate of time decay than the time remaining.  When options are far OTM or deep ITM, things are just different.  Once you understand that situation (as I'm certain you do now), the theta problem goes away. Once an option has only a small time premium remaining, it cannot keep losing value at the same rate – or else it would become worth less than zero.

Iron Condors

Time decay is what makes trading iron condors profitable. Sure it may be good to own the position when time decay is most rapid, but that is not the 60 to 30-day iron condors that you envision.  That would work only when the calls and puts are both quite far OTM.  That means a tiny premium to start the trade.  That's a non-starter for me.

In the real world of condor trading, most options are not that far OTM and have enough time premium to belong in the standard decay group.  When markets behave for premium sellers, the last 30 days are the periods with the most rapid time decay.  For most iron condor traders, that is the ideal situation. However, that's also the period of highest risk – due to negative gamma.  For me, collecting the fastest time decay is not as important as owning a less risky trade.

863

Liberty

Peace on Earth.  Liberty for all.  Best wishes for 2011

 

 

Read full story · Comments are closed

Elementary Questions on the Greeks

Don has some questions regarding delta and gamma that are worth posting (edited for brevity, when possible). 

If you understand the principles, then using the Greeks becomes far less frightening. 

The Greeks serve one purpose.  They allow a trader to measure risk.  That's it.  They do no more than that.  If the risk is within your boundaries, you can be comfortable with the trade.  If not, you can easily change any specific risk factor.  That's the beauty of using options.  Risk is readily measured and controlled. You cannot do that with stock, currencies, commodities etc.  Options are special.

***

Hi Mark,

You often mention the effect of Gamma on front
month trading. Are there strategies that use Gamma advantageously for
the trader? 

Don, 

Advantageously?  Are you saying that + gamma is advantageous and negative gamma is not?  If you want positive gamma, you must PAY for it.  It is not free. If you want gamma, there are strategies to suit: long options, buy straddles, back spreads etc.

You freely choose iron condors (and others) that benefit from positive time decay.  Negative gamma is part of the package. 


Time decay of options is not linear, and graphs show that the last six weeks prior to
expiry has the most dramatic theta effect. Would you explain the positive
and negatives of this trade and have you ever considered trading IC's
in this time frame? 

1) That is not anywhere close to having the 'most dramatic theta effect.'  Any position with less time is even more dramatic. 

The 'most' dramatic theta effect occurs when your option is exactly ATM, it is one minute prior to the closing bell on the 3rd Friday, and news is pending within the next 10 seconds.

2) The positives and negatives of this trade are exactly the same as ANY OTHER iron condor trade.  More time = higher premium, less theta, and less negative gamma. It's always a compromise.  Choose the combination of pluses and minuses that suit you.  Don't let anyone tell you that there is a 'best' time frame for you.

3) I consider trading iron condors in ANY time frame.  For me, front-month trades almost never survive the first elimination round.


Buying LEAPS and selling calls against them: Let's say that an option
trader believes that a stock will rally in less
than 24 months.

If a trader continued to sell options against LEAPS [MDW: assuming the shorts conveniently expire worthless], by the time the long option approached expiry, that could pay for the call and he/she would still own the Jan 15 calls – an ITM option.

Yes,the stock may go below 15, with the LEAPS losing value – but are there other negatives to this strategy? 

Don, I have discussed the idea of using LEAPS in 'covered call' and collar strategies a bunch of times.

Bottom line: Yes, there's big risk.  A big market move or a big decline in implied volatility demolishes this strategy.  See those, and other, posts for explanations.


PUT: if a trader were bearish on a stock, how would the LEAPS work with
Puts? Buy the ITM Put and sell OTM puts against it? 

That's one method.



A web site I saw recommended selling calls and puts on a stock
you like – at the same time. I get worried about this. Anytime you sell,
you have an OBLIGATION rather than a RIGHT and you never know when a
black swan event will hit an individual stock. But I was thinking that
this may be more acceptable on an index, I'd like to hear your opinion.

Who in his/her right mind would sell a naked call on a stock he/she likes?  I assume you already own, or are willing to buy the stock to make this play.  Don, this is merely covered call writing.  The long stock and short call is a covered call.  The naked put is equivalent to a covered call.

Covered call writing has downside risk.  If you don't like the risk, don't make the play.  If you don't want to be obligated to buy shares at the strike, then don't sell puts.

Indexes tend to be less volatile than individual stocks, so yet, this idea is a bit better when using index options.  You would have to buy something to represent the underlying stock.

A follow up on Gamma. Today F is trading at 13.20 and the
Sep 13 Call has a 57 Delta and 22 Gamma (am I correct that like Delta
you simply remove the decimal to factor in Gamma?)  Meaning (to me) that  Delta of the 13 Call will be 77
if it moves up and 35 if it moves down. Is this right? 

The gamma is per share, so multiply by 100 to get gamma per contract. 

Is this right? To a point.  I thought you would know that gamma is not constant and changes as the stock price changes.  Thus, the call delta changes by more than you anticipate (higher gamma at the end of the move than at the start) when the stock rises and by less when it declines (final gamma declines during stock price slide).  But what you have is a reasonable estimate.

If I move out to Dec, gamma is
less. The
reasoning behind this is: as the front month option moves into the money and it is
near expiration, gamma is more pronounced due to the reduction in
time, is this the correct view? 

Yes.  When there is less time, there is less chance that the option will move OTM or ITM.  Thus, delta moves towards 100 or 0 much more quickly.  For delta to change so rapidly, gamma must be higher. 

756

Read full story · Comments are closed

Loving Positive Theta and Trading Calendar Spreads II

Part I

Follow-up: I did not mean to sound naive when I said that I don't care about short term movements.  I
tend to take a macro view of my positions.  I trade options just on
index options or index ETFs and I filter out the daily "noise."  I let the market ebb and flow and don't make too many
adjustments.

If the number of adjustments is sometimes > zero, then you are in the game.

I am conservative with the # of contracts so that a big market
swing is not going to cause much damage to the overall account.

Good. Position size is the #1 step when managing risk

In response to your comments about what would I do if the market
increases and my long put loses value: I would roll up my short position
to create a bull spread, presumably collecting enough premium to offset
the decline in the long position.

If I understand your plan correctly, the newly opened short put has a higher strike than your long put (hence you are now short a put spread). 
Roll too far and you suddenly have nightmarish downside risk.  Do you
really want (for example) to own a Dec 800 put against a Nov 850 put? 
How is that a calendar spread?

Be careful when adjusting. Do not own a new
position when that position has far more risk than you prefer.  It's
better to exit, take the loss, and begin again.

I would not allow my short position to get too far ahead of my long position so that the position became too risky.

OK. 
That's the goal.  Not so easy to do when you want to 'roll up' the put
to recover enough cash to cover the loss from your long LEAPS put.

 
I did a 6-year back test of this strategy from 2004 – 2009 following this basic criteria:

1) buy 2-3 year Put ATM or slightly ITM.

This is a HUGE vega play, and to me, dwarfs your theta play.

[Side comment:  IV
skyrocketed during 2008-9.  If you  already owned your long-term put
before the IV rise, you fared far better than if you had to buy the put
when IV was near 90.  Consider the effect of this on the back test
results]

2) sell 1 month ATM, allowing myself to roll up my short position each month so that I'm selling ATM. 

Problems:
This ignores how far ITM or OTM your long option is.  Thus, it ignores
all Greeks. This may be a viable play, but it is NOT trading calendar
spreads. In a calendar, strikes are identical.  You are trading a
variety of diagonal spreads.

3) If the market declined to the point that I couldn't get $1 or so
rollover for each short put, I would close both legs and
re-establish the spread using ATM prices.  This happened during the 2008
crash.

Closing
both legs and opening a new ATM position during the crash means you had
to buy LEAPS puts when IV was HIGH.  All time record high (excluding
Oct 1987).  How could you convince yourself (in the real world, not in a
back test) to pay such a gigantic price for LEAPS puts?  How can anyone
anticipate a profit knowing that IV is going to decrease?

How can you earn a profit buying ATM puts in
a volatile market?  The strike you own soon becomes far OTM, reducing
the value of the time spread.

4)  As the market increased, I would increase my short strike price
to be ATM but would not let my short position to get more than 20
strikes ahead of my long position.

Twenty
strikes?  20 SPY points is a 20% market move. Near the bottom it was > 20%.  

Please understand:  I find this far too
risky.  You may find it a great strategy, especially when you have back
tested it.  But know this:  This is not a calendar spread
This is not a theta play.  This is a play on vega. Plus, you are seldom
near delta neutral – and negative gamma continuously makes that worse. 

How can you own,
for example, a LEAPS 85 put and sell an ATM, front-month 100 put and
feel hedged?  You lose money on a big downside move and lose on a rally
with an IV crunch.

I must be missing something here.

This caps the risk.

The question becomes: Is that cap at an acceptable level, or is it too high? 

If the market increased substantially from my strikes, I would close both positions and re-establish.

Based on your comment, it seems to me that 'substantially' means more than 20 strikes.

Do
you recognize that selling ATM options gives you the maximum + theta that you
seek, but that it comes with maximum negative gamma?  This is not a conservative
play.


5)  I did one spread for every $2,500 of cash in the account,
thereby having enough cash on hand to handle adjustments and lower the
risk of the overall account.

I
see the possibility of losing half of that $2,500 overnight.  Obviously
that did not happen.  How big was the largest draw down?

This 6 year back test netted performance of approximately 25% per year.

Nice result. Do
you trust that period of time as being typical? 

Because I was satisfied with the back test, I started trading this
with real money in January of this year.  YTD, I am up almost 10%
compared to a down S&P 500.

Your benchmark is not the S&P.  Your trades have nothing whatsoever to do with market direction.

The important question for you: Is this return sufficient to justify the risk?  You may feel there is little risk, making this question easy to answer. Because nothing
terrible seems to have happened during very turbulent markets, the risk
may be less than I fear.

There is no reason to abandon a
successful strategy.  But be careful: Overconfidence can be a killer.

My
question remains:  Why are you making money?  It is truly from theta? 
Is it from vega?  Is it from lucky market moves?  Is it from making
skillful and timely adjustments?

This strategy is not a 'set it and forget it.'  Thus, it's important to know from whence come the profits.

 

Anyway, thanks again for your feedback.  I look forward to learning
more through your book which I just bought.

Thanks

752



Subscribe To Barron's Magazine
Read full story · Comments are closed

Loving Positive Theta and Trading Calendar Spreads

Another good set of questions

1)  I am a big fan of calendar spreads because I like the idea of selling time value.

I'm sure you are aware, but other strategies allow time value to be sold, including covered all writing and credit spreads.

The definition of a calendar spread includes the requirement that both options have the same strike price.

All other variables of option prices are unpredictable, but the
passage of time is something you can count on.  Most books
describe calendars using calls, with the long position expiring only a few months after the short position.

It seems to me that using puts is more
advantageous: I can get more
for an OTM put than I can for an OTM call, therefore I'm selling more
time value.

You are also pay more for the long puts. 

An important decision: – Calendars perform poorly when the market
moves far away from the strike.  Thus, choosing OTM calls vs. puts
should be partially concerned with getting the strike price right.

Also, I have been buying LEAPS as my long position.  I look at my long put position as a life insurance policy,

That is NOT realistic.  No one hedges a life
insurance policy by selling short term policies against the main
policy.  If the market makes a gigantic move through your strike price,
you no longer have any insurance.

and I want the cheapest per month premium I
can get.  For example, this Jan I bought a Dec 2012 SPY 115 put
for approximately $19.  The cost of this insurance is just
over $.50 / month.  If I bought a 6-month put, the cost per month
would have been substantially higher.

I understand your plan.  But what are you going to do with that $19 put when the market moves much higher, IV gets crushed, and the put has declined to $8?

Am I missing something here?

You are
ignoring gamma risk – i.e., the BIG move.  Obviously calendars do best
when the market does not make a giant move.  But the market must remain sufficiently volatile such that IV
(implied volatility) doesn't decline by enough to destroy the
value of your LEAPS or severely diminish the price of the short-term puts – the options you sell every month.

This idea is so dependent on IV that it is really a vega play and not a theta play.  At least, that's how I see it.

So far, this strategy has proven to work pretty well,

Over what period of time?

but I'd be interested in hearing your opinions on using Puts and also using LEAPS.

Puts
are okay – but please evaluate how much extra you must pay for the LEAPS puts to determine whether this idea is truly better than using calls.

LEAPS are
not for me – unless IV is very low.  Buying LEAPS options is a big play on
vega
and future IV.

Question: Are you playing calendar spreads to play theta (as you said), or vega?  How much vega risk are you willing to take?  Only you can answer.

 

2)  My understanding is that
the Greeks help you understand short term movement in your overall
position.  If you set up a position with an eye towards the profit/loss
graph at expiration, the Greeks will only help you understand how your
position will react short-term.   When I set up a position, I'm not too concerned with short term movement, but only focus on the ultimate profit/loss potential….so if that's the case are the Greeks less important? 

IMHO, this is a naive and dangerous question.  Fortunes are made and lost before expiration arrives.

The
Greeks serve one purpose.  They allow you to measure risk.  Then, the trader accepts that
risk or reduces it.

My philosophy is that a
trader must avoid the big hit.  If you ignore
everything that happens between today and expiration, how can you avoid
that occasional big loss?

What if the
market rallies and your $19 put loses value day after day.  At what
point to do stop that bleeding?  Never?

If you plan to hold positions through expiration, regardless of risk during the interim
(I shudder at the thought, but understand it's your decision) I
believe the strategy is doomed to failure because the most important factor in your future success is how well you manage risk.

Take the gambling aspect out of the equation.  I recommend considering position risk, defining your comfort zone, and trading accordingly.  That is risk management.

 

3)  Finally, another question about the Greeks:  I understand Delta, Theta and to a lesser extent, Vega. 

Nutshell version:  When IV increases by one point, option prices increase by their
vega.  The more vega you own, the better you do when IV increases.

But I have a lot of trouble wrapping my mind
around Gamma.  I know the definition that it measures the change in
Delta, but how does one use Gamma to structure a position? 

It measures the rate at which delta changes. If
you are selling gamma – and you are – you want to know how much money
you anticipate losing if the underlying moves X points.

Let's say you lose $1,000
on a two point move (delta ~ -500).  Then lose $1,200 on the next
two points (delta ~ -600) and $1,500 on the next two (delta ~ -750).  If the rate at which those
losses are accelerating is too high – if the risk is outside your zone – then you are short too much gamma. 
'Structure' your trade differently.

One way to do that is to
reduce position size.  Trade 10 or 20% fewer spreads. 

Or own some
protection (buy something useful (not father OTM than your short option)
that has + gamma, even though it is going to cost some of that precious
time decay).  Even a 1-lot pays dividends on a large move.

The point is to be aware of gamma, decide if it's too high, and adjust the trade accordingly.

I need to continue studying Gamma. 

When
replying to questions such as you raised, it's very helpful to have an
idea how long you have been using options.  I'm sure you can see that my
reply to a brand new option trader would not be the same when the
questioner has been trading for 5 years.  If you are a 5-year trader,
I's a bad idea to not know more about the Greeks.

If new to
options, I'd encourage you to spend some time in learning to understand what the Greeks
can do for you (even though it is only to measure risk; this is
important).

For example, Delta is easy to remember
because it's always positive for Calls, negative for Puts.  How Gamma
works is not as intuitive as the other Greeks.  I will continue my
reading on this area.

Gamma is the same for the
put and the call (same strike and expiry).  Gamma is always +.  If you
own the option, you get + gamma.  If you sell it, you accumulate negative
gamma.


Vega is always +.  All options increase in value when the
implied volatility rises.  Own an option, you have + vega.  Sell it,
negative vega.

Same with theta.  All options decay.  Options have negative theta.  Sell the option, and you have + theta.  Own it and it's negative.


Tomorrow, a follow-up conversation.  To be continued

751

Read full story · Comments are closed

Establishing Trading Rules: How Much Experience is Needed?

Mark,

Based on what I learned and thought about over the past few days due to my
trades:

  • I would now only buy calls/puts in the front month. The
    odds are more with us [MDW: Us? How did I get involved?]  because of gamma. Is this thinking correct?
  • The
    loss is limited to premium paid, but the upside is huge

     
  • I would
    never buy otherwise because theta is the enemy

  • I am not sure what I
    would buy though, ATM or 2 levels OTM.

 

Slightly off-topic: Based on looking at my trades, time decay is not
linear. The more the underlying is at a particular strike, the more the
time decay at that strike.

Is the time decay calculated per day or week
to week?

The time decay graphs given in most literature gloss
over the fact that those decay graphs are concerned with an option which stays
exactly ATM all the time. Why?  The real spot price gyrates?

Thanks

Amit

***

I get it.  You are an eager student.  You want to trade options right now and make money today.  Every time you see a piece of evidence about a specific strategy, you believe you found the Holy Grail.  I can only tell you that you are making a huge mistake.

You are FAR TOO INEXPERIENCED to make these decisions.

This is learning time.  This is experiment time. 

You cannot make a few trades and reach a permanent-sounding decision such as: 'I would only buy front-month options.'  If you reached this decision, on what is the thought process based?  How many times have you traded 2nd or 3rd month options?  How did the results compare?  Did you make good money by correctly predicting direction, or did something else happen that made the trades profitable.

It is wrong to assume that a profitable trade means you are a genius. 


It is wrong to assume that a losing trade is the result of a mistake.

You must compare the trade with others and discover why the trade was profitable (or not).  The 'why' is how you learn.

NOW is your chance to trade a variety of ideas, analyze the results, keep detailed records, think about the results and make an attempt to get a feel for what works and where to establish risk limits you can handle.

1) No the odds are not with you because of gamma.  The odds are not with you, period.  You have much less time to be right in your prediction.  If it does not happen soon, time decay will eat away at the value of your options.

How can the odds ever be with you when you must predict the direction of the move, the timing of the move, the size of the move?  You must be a very skilled market timer with a PROVEN track record before you can have any expectation of making money when buying options.

I'd hate to see your enthusiasm disappear down a sink hole.  Didn't you try this 'buying options' strategy once before?

2) Yes the Reward to risk ratio is excellent.  But the probability of success is not.

3) I don't understand the 3rd point.  When you buy front-month options, theta is the big enemy.

4) This is your problem in a nutshell.  You want to buy. You think buying and owning positive gamma puts the odds of success on your side.  But you give no consideration to how far the stock must move.  You don't know which options to buy.

It doesn't work that way.  The whole strategy requires knowing which options to buy, or having a method for deciding.  It's not a random selection.  It you cannot estimate the size of the move you should not be buying options.

Buying out of the money options is very much a gamble.  Some players succeed. I have no idea where your talents lie, but if you are excellent (proven track record), you can win this game.  Otherwise, not a chance.  Especially when you buy OTM options.

Off topic:  Time decay is NOT linear.  ATM options have the most time premium and thus, the most rapid time decay.  Time decay of American style options is based on the amount of time remaining until the market closes for trading on expiration Friday. 

The decay can be determined for one week, one day, one second, or any other time period you care to mention.  However, the Greek theta measures the time decay for one day.  Theta tells you how much value the options loses overnight.

Most option analytical tools that measure something specific, such as theta, assume all else is constant.  It MUST be this way.  If you want to know about theta, then if anything is not constant, that item will also affect the option price, and you will NOT be able to tell what part of the option price change is due to theta.  Please tell me that you understand this is true.

One of my basic tenets is that it is very foolish to trade when you don't understand the rules.  Some rules (automatic exercise) can come as quite a surprise to the novice. Other properties of options (how quickly they decay as expiration nears; or the sale of options is not free money) may not be immediately obvious.  But it makes no sense to use tools  when you don't know how to use them.

What's your hurry?  You have the rest of your life to trade. 

Practice in a paper-trading account or trade small size in your real account.  But don't go jumping to conclusions based on one or two trades.

746

July 2010 Expiring Monthly.  Table of Contents:

1007_TOC

Read full story · Comments are closed