How is the time-premium on PUT options calculated
I asked a friend and he gave me a good explanation, so I'm just gonna paste it here for others: There is a simple and a complex answer depending on how much you want to understand the pricing dynamic of options.  LEAPs don't react 1:1 with a stock move because the probability of your option being in the money at expiry is still very much up in the air so you basically don't get full credit for a move in the stock this far out from expiry. The more complex answer involves a discussion of option 'greeks'.  Delta, Gamma, Theta, Vega, and Rho are variables that affect the pricing of all options.  The key greek in this case is Delta because it describes mathematically the expected move of an option as a ratio vs changes in stock price.  For put options the ratio is -1 to 0 where -1 is direct correlation between stock price and option price and 0 is no correlation.  The Delta increases as an option gets deeper in the money and also as it gets closer to expiry and reflects the probability of the option expiring in the money.  For your option contract the current Delta is -0.5673  so -3.38 * -0.5673 = 1.9 which is close.  Also keep in mind that that strike price had a last trade at 12:03 when the stock was at 13.3 and the current ask price is 22.30 so the last price isn't a true reflection of the market value.   As for the other greeks, Gamma is a reflection of volatility in the sense that it affects the rate of change of Delta as price and time changes.  Theta is the value of the time component of the option and is expressed as the expected time decay per day.  The problem is that the time premium is really some arbitrary number that the market maker seems to be able to change at will without justification and it can fluctuate wildly over short periods of time and I think this may explain some of the discrepancy.   If you bought the options when AAPL was $118.68 a couple weeks ago (option price of $18.85) and now AAPL is at $112.34 and the Delta over that time averaged at -0.55 then your expected option price would be $22.34 (($118.68 - $112.34) * 0.55 + 18.85 = $22.34) so you lost around $0.24 in time premium or 'Theta burn' over the last 2 weeks assuming it opens trading around 22.1 on Monday. Your broker should have information about the option contract greeks somewhere.  For my platform I have to put the cursor over top of the option contract for it to show me the greeks.  If your broker doesn't have this then you can get it from nasdaq.com. This is another reason that I only invest in deep in the money LEAPs because the time premium is much much lower than near the money and also because delta is much higher so if I want to trade out of it early I don't feel like I'm getting ripped off not getting paid for a stock price move.  For example look at the Jan 17 175 put.  The Delta is -0.9 and the time premium is only $0-1 depending if you are looking at the bid or ask.  The only downside is expected returns are lower for deep in the money contracts and they are expensive to buy. "According to Yahoo, AAPL was trading at $113.26 at 1:10 PM on 11/13/15, which is the approximate time of your option quote.  You provided a quote for AAPL at 4:15, and the stock happened to keep going down most of the that afternoon.  To make a sensible comparison, you need to take contemporary prices on both the stock and the option.  The quote on the option also shows the ""price"" being outside of the bid-ask range, which suggests that the option was trading thinly and that the last price occurred sometime earlier in the day.  If you use a price in the bid-ask range ($21.90-$22.30) and use the price of AAPL at the time of the put quote, you'll come up with a price that's much closer to your expectation."
"Suddenly its not just comparing the current price to the price of the contract, or is it? Sure it is.  Suppose you bought 100 option contracts (each for 100 shares) and paid a $1 per share premium ($10,000 total).  Now those options are trading for $1.50 per share.  You have an unrealized $0.50 gain per share, or $5,000. The $10,000 in options you bought are now worth $15,000.  It holds whether they were bought to open or close a position, or whether they are puts or calls.  The only difference is whether you bought or sold the options (the arithmetic is just reversed for selling an option). But lets say we have an Option, where the payoff is max(St-K, c0) where ct is the market price. What do you do then? Your current, unrealized P&L is different than the payoff.  The payoff only happens at maturity.  The current P&L is based on current market prices, just like stock.  Option prices all have a ""time premium"" making them worth more than their payoff (intrinsic) value prior to maturity." "Cart's answer describes well one aspects of puts: protective puts; which means using puts as insurance against a decline in the price of shares that you own.  That's a popular use of puts.  But I think the wording of your question is angling for another strategy: Writing puts. Consider: Cart's strategy refers to the buyer of a put.  But, on the transaction's other side is a seller of the put – and ultimately somebody created or wrote that put contract in the first place!  That first seller of the put – that is, the seller that isn't just selling one they themselves bought – is the put writer. When you write a put, you are taking on the obligation to buy the other side's stock at the put exercise price if the stock price falls below that exercise price by the expiry date.  For taking on the obligation, you receive a premium, like how an insurance company charges a premium to insure against a loss. Example:  Imagine ABC Co. stock is trading at $25.00.  You write a put contract agreeing to buy 100 shares of ABC at $20.00 per share (the exercise price) by a given expiration date.  Say you receive $2.00/share premium from the put buyer.  You now have the obligation to purchase the shares from the put buyer in the event they are below $20.00 per share when the option expires – or, technically any time before then, if the buyer chooses to exercise the option early. Assuming no early assignment, one of two things will happen at the option expiration date: ABC trades at or above $20.00 per share. In this case, the put option will expire worthless in the hands of the put buyer.  You will have pocketed the $200 and be absolved from your obligation.  This case, where ABC trades above the exercise price, is the maximum profit potential. ABC trades below $20.00 per share.  In this case, the put option will be assigned and you'll need to fork over $2000 to the put buyer in exchange for his 100 ABC shares.  If those shares are worth less than $18.00 in the market, then you've suffered a loss to the extent they are below that price (times 100), because remember – you pocketed $200 premium in the first place.  If the shares are between $18.00 to $20.00, you're still profitable, but not to the full extent of the premium received. You can see that by having written a put it's possible to acquire ABC stock at a price lower than the market price – because you received some premium in the process of writing your put.  If you don't ""succeed"" in acquiring shares on your first write (because the shares didn't get below the exercise price), you can continue to write puts and collect premium until you do get assigned. I have read the book ""Money for Nothing (And Your Stocks for FREE!)"" by Canadian author Derek Foster.  Despite the flashy title, the book essentially describes Derek's strategy for writing puts against dividend-paying value stocks he would love to own.  Derek picks quality companies that pay a dividend, and uses put writing to get in at lower-than-market prices.  Four Pillars reviewed the book and interviewed Derek Foster: Money for Nothing: Book Review and Interview with Derek Foster. Writing puts entails risk.  If the stock price drops to zero then you'll end up paying the put exercise price to acquire worthless shares!  So your down-side can easily be multiples of the premium collected.  Don't do this until and unless you understand exactly how this works.  It's advanced. Note also that your broker isn't likely to permit you to write puts without having sufficient cash or margin in your account to cover the case where you are forced to buy the stock.  You're better off having cash to secure your put buys, otherwise you may be forced into leverage (borrowing) when assigned.  Additional Resources: The Montreal Exchange options guide (PDF) that Cart already linked to is an excellent free resource for learning about options.  Refer to page 39, ""Writing secured put options"", for the strategy above. Other major options exchanges and organizations also provide high-quality free learning material:" What Jaydles said. I think of each strategy in terms of Capital at Risk (CaR). It's a good thing to know when considering any position. And then conveniently, the return is always profit / CaR. With covered calls it's pretty easy. Pay $1000 for stock, receive $80 in premium, net CaR is $920.  If you own the stock and write calls many times (that expire worthless, or you that you buy back), there are two measurements to consider. First, treat every covered call as a buy-write. Even if you already own the stock, disregard the real cost basis, and calculate from the moment you write the call, using the stock price at that time. The second measure is more complicated, but involves using something like the XIRR function in a spreadsheet. This tracks the series as a whole, even accounting for times where there is no written call outstanding. For the written put, even though your broker may only require 30% collateral in a margin account, mentally treat them as cash-secured. Strike less premium is your true CaR. If the stock goes to zero by expiration, that's what you're on the hook for. You could just compute based on the 30% collateral required, but in my view that confuses cash/collateral needs with true risk. Note: a written put is exactly identical to a covered call at the same strike. If you tend to favor puts over CCs, ask yourself why. Just like a loaded gun, leverage isn't inherently bad, but you sure want to know when you're using it. Suppose you're writing a put with a strike price of 80. Say the share's(underlying asset) price goes down to 70. So the holder of the put will exercise the option. Ie he has a 'right to sell' a share worth 70 for rs 80. Whereas a put option writer has an 'obligation to buy' at rs 80 a share trading at rs 70. Always think from the perspective of the holder. If the holder exercises the option, the writer will suffer a loss. Maximum loss he suffers will be the break even FSP, which is Strike price reduced by the premium paid.. If he doesn't exercise the option the writer will make a profit, which can maximum be the put premium received. What Jaydles said. I think of each strategy in terms of Capital at Risk (CaR). It's a good thing to know when considering any position. And then conveniently, the return is always profit / CaR. With covered calls it's pretty easy. Pay $1000 for stock, receive $80 in premium, net CaR is $920.  If you own the stock and write calls many times (that expire worthless, or you that you buy back), there are two measurements to consider. First, treat every covered call as a buy-write. Even if you already own the stock, disregard the real cost basis, and calculate from the moment you write the call, using the stock price at that time. The second measure is more complicated, but involves using something like the XIRR function in a spreadsheet. This tracks the series as a whole, even accounting for times where there is no written call outstanding. For the written put, even though your broker may only require 30% collateral in a margin account, mentally treat them as cash-secured. Strike less premium is your true CaR. If the stock goes to zero by expiration, that's what you're on the hook for. You could just compute based on the 30% collateral required, but in my view that confuses cash/collateral needs with true risk. Note: a written put is exactly identical to a covered call at the same strike. If you tend to favor puts over CCs, ask yourself why. Just like a loaded gun, leverage isn't inherently bad, but you sure want to know when you're using it. "Option pricing models used by exchanges to calculate settlement prices (premiums) use a volatility measure usually describes as the current actual volatility.  This is a historic volatility measure based on standard deviation across a given time period - usually 30 to 90 days.   During a trading session, an investor can use the readily available information for a given option to infer the ""implied volatility"".  Presumably you know the option pricing model (Black-Scholes).  It is easy to calculate the other variables used in the pricing model - the time value, the strike price, the spot price, the ""risk free"" interest rate, and anything else I may have forgotten right now.  Plug all of these into the model and solve for volatility.  This give the ""implied volatility"", so named because it has been inferred from the current price (bid or offer). Of course, there is no guarantee that the calculated (implied) volatility will match the volatility used by the exchange in their calculation of fair price at settlement on the day (or on the previous day's settlement).  Comparing the implied volatility from the previous day's settlement price to the implied volatility of the current price (bid or offer) may give you some measure of the fairness of the quoted price (if there is no perceived change in future volatility).  What such a comparison will do is to give you a measure of the degree to which the current market's perception of future volatility has changed over the course of the trading day.   So, specific to your question, you do not want to use an annualised measure.  The best you can do is compare the implied volatility in the current price to the implied volatility of the previous day's settlement price while at the same time making a subjective judgement about how you see volatility changing in the future and how this has been reflected in the current price." "You'd need to know the delta and the theta of the option. You can either calculate them yourself using a model like Black-Scholes (assuming you have a market price and can imply a volatility, and know the other factors that go into the model) or, you can see if your broker quotes ""greeks"" as well (mine does). The delta is the sensitivity (rate of change in value) to the underlying stock price, and the theta is the sensitivity to time passing (usually expressed in $/day).  So if your option has a delta of .5 and a theta of -.04, when one day passes and the underlying stock goes up $3, the option will gain roughly $1.50 due to the underlying stock price and lose $0.04 due to time passing." Ok, so disregarding passivity, could you help me through a simplified example?   Say I only had two assets, SPY and TLT, with a respective weight of 35 and 65% and I want want to leverage this to 4x.  Additionally, say daily return covar is:  * B/B .004% * B/S -.004% * S/S .02%   Now, if I read correctly, I should buy ATM calls xxx days in the future.  Which may look like: Ticker, S, K, Option Price, Delta, Lambda  * TLT  $126.04  $126.00  $4.35  0.50  14.5 * SPY  $134.91  $134.00  $6.26  0.55  11.8  ^ This example is pretty close but some assets are far off.   I feel like I'm on the wrong track so I'll stop here.    I just want to lever up my risk-parity. Margin rates are too high and I'm docked by Reg-T.