Exercise a put option when shorting is not possible
You can buy a put and exercise it. The ideal option in this case will have little time premium left and very near the money. Who lent you the shares? The person that sold you the option! In reality, when you exercise,  assignment can be random, but everything is [supposedly] accounted for as the option seller had to put up margin collateral to sell the option. You are the one lending yourself the shares to sell;you purchase the stock at market price and sell at the strike price of the option to the put seller when you exercise the option.
The crucial insight is that the alternative to early exercise of an American call is not necessarily to hold it to expiry, but to sell it. And selling it, at its value, is always better than exercising it.  Note that this holds only for options on assets that don't pay dividends. Here's the proof, using Put-Call-Parity. We know that at expiry T, we have (using a Call and a Put both struck at K): C(T) - P(T) = S(T) - K (if this is not clear to you, consider the case where S is less than, equal to, or greater than K at maturity, and go through each of them.) If the stock S doesn't pay any dividends (and there is no cost of carry etc.), we can replicate both sides now at time 0; we just buy one call, sell one put (that gives us the left hand side), buy the stock, and borrow money so that at time T we have to repay K (that gives us the right hand side). That means that now, we only need to borrow df * K, where df is the discount factor, and is less than one (assuming the good old pre-2009 world where interest rates are positive). Thus: C(0) - P(0) = S(0) - df * K.  Rearranging gives: C(0) = S(0) - df * K + P(0).  That's the value of the call, if we sell it (or hold it). However, if we exercise, we only get: C_ex = S(0) - K Now, we see that C(0) > C_ex, because we subtract less (df*K < K), and add P(0). It would be nice if the broker could be instructed to clear out the position for you, but in my experience the broker will simply give you the shares that you can't afford, then freeze your account because you are over your margin limit, and issue a margin call. This happened to me recently because of a dumb mistake: options I paid $200 for and expected to expire worthless, ended up slightly ITM, so they were auto-exercised on Friday for about $20k, and my account was frozen (only able to close positions).  By the next Monday, market news had shifted the stock against me and I had to sell it at a loss of $1200 to meet the margin call.  This kind of thing is what gives option trading a reputation for danger: A supposedly max-$200-risk turned into a 6x greater loss.  I see no reason to ever exercise, I always try to close my positions, but these things can happen. "One alternative strategy you may want to consider is writing covered calls on the stock you have ""just sitting there"".  This will allow you to earn a return (the premium from the calls) without necessarily having to give up your holding. As a brief overview, ""options"" are derivatives that give the holder the right (or option) to buy or sell shares at a specified price.  Holders of call options with a strike prike $x on a particular security have the right to purchase that security at the strike price $x.  Conversely, holders of put options with a strike price of $x have the right to sell that security at the strike price $x.  Always on the other side of a call or put option is a person that has sold the option, which is called ""writing"" the option.  If this person writes a call option, then he will be obligated to sell a certain amount of stock (100 shares per contract) at the strike price if that option is exercised.  A writer of a put option will be obligated to by 100 shares per contract at the strike price if that option is exercised. Covered calls involve writing call contracts on stock that you own.  For example, say you own 100 shares of AAPL, and that AAPL is currently trading for $330.  You decide to write a Jan 21, 2012 call on these shares at a strike price of $340, earning you a premium of say $300. Two things can now happen: if the price of AAPL is not at least $340 on January 21, then the options are ""out of the money"" and will expire unexercised (why exercise an option to buy at $340 when you can buy at the currently cheaper market price?).  You keep your AAPL stock plus the $300 premium you earn.  If, however, the price of AAPL is greater than $340, the option will be exercised and you will now be required to sell the shares you own at $340.  You will earn a return of $10/share ($340-$330), plus the $300 premium from the call option.  You still make out in the end, but have unfortunately incurred an opportunity cost, as had you not written the call option you would have been able to sell at the market price, which is higher than the $340 strike price. Covered calls are considered relatively safe and conservative, however the strategy is most effective for stocks that are expected to stay within a relatively narrow price range for the duration of the contract.  They do provide one option of earning additional money on stocks you are currently holding, albeit at the risk of giving up some returns if the stock price rises above the strike price." Shorts need a buyer on the other end somewhere, if there is no one interested in taking the other side of it, you probably won't find anywhere you will be able to execute that trade. Take a look on your broker's site, see if it's an option they will even give you. In the money puts and calls are subject to automatic execution at expiration. Each broker has its own rules and process for this.  For example, I am long a put. The strike is $100. The stock trades at the close, that final friday for $90. I am out to lunch that day. Figuratively, of course. I wake up Saturday and am short 100 shares. I can only be short in a margin account. And similarly, if I own calls, I either need the full value of the stock (i.e. 100*strike price) or a margin account.  I am going to repeat the key point. Each broker has its own process for auto execution. But, yes, you really don't want a deep in the money option to expire with no transaction.  On the flip side, you don't want to wake up Monday to find they were bought out by Apple for $150. I can't speak for all brokerages but the one I use requires cash accounts to have cash available to purchase the stock in this situation. With the cash available you would be able to purchase the stock if the option was exercised.  Hope this helps I would expect that your position will be liquidated when the option expires, but not before. There's probably still some time value so it doesn't make sense for the buyer to exercise the option early and take your stock. Instead they could sell the option to someone else and collect the remaining time value. Occasionally there's a weird situation for whatever reason, where an option has near-zero or negative time value, and then you might get an early exercise. But in general if there's time value someone would want to sell rather than exercise. If the option hasn't expired, maybe the stock will even fall again and you'll keep it. If the option just expired, maybe the exercise just hasn't been processed yet, it may take overnight or so. To expand on the comment made by @NateEldredge, you're looking to take a short position.  A short position essentially functions as follows:  Here's the rub: you have unlimited loss potential.  Maybe you borrow a share and sell it at $10.  Maybe in a month you still haven't closed the position and now the share is trading at $1,000.  The share lender comes calling for their share and you have to close the position at $1,000 for a loss of $990.  Now what if it was $1,000,000 per share, etc. To avoid this unlimited loss risk, you can instead buy a put option contract.  In this situation you buy a contract that will expire at some point in the future for the right to sell a share of stock for $x.  You get to put that share on to someone else. If the underlying stock price were to instead rise above the put's exercise price, the put will expire worthless — but your loss is limited to the premium paid to acquire the put option contract. There are all sorts of advanced options trades sometimes including taking a short or long position in a security.  It's generally not advisable to undertake these sorts of trades until you're very comfortable with the mechanics of the contracts.  It's definitely not advisable to take an unhedged short position, either by borrowing someone else's share(s) to sell or selling an option (when you sell the option you take the risk), because of the unlimited loss potential described above. "You're forgetting the fundamental issue, that you never have to actually exercise the options you buy.  You can either sell them to someone else or, if they're out of the money, let them expire and take the loss. It isn't uncommon at all for people to buy both a put and call option (this is a ""straddle"" when the strike price of both the put and call are the same). From Investopedia.com: A straddle is an options strategy in which the investor holds a position in both a call and put with the same strike price and expiration date, paying both premiums. This strategy allows the investor to make a profit regardless of whether the price of the security goes up or down, assuming the stock price changes somewhat significantly.   Read more: Straddle http://www.investopedia.com/terms/s/straddle.asp#ixzz4ZYytV0pT" "The other two answers seem basically correct, but I wanted to add on thing:  While you can exercise an ""American style"" option at any time, it's almost never smart to do so before expiration.  In your example, when the underlying stock reaches $110, you can theoretically make $2/share by exercising your option (buying 100 shares @ $108/share) and immediately selling those 100 shares back to the market at $110/share.  This is all before commission. In more detail, you'll have these practical issues: You are going to have to pay commissions, which means you'll need a bigger spread to make this worthwhile.  You and those who have already answered have you finger on this part, but I include it for completeness. (Even at expiration, if the difference between the last close price and the strike price is pretty close, some ""in-the-money"" options will be allowed to expire unexercised when the holders can't cover the closing commission costs.) The market value of the option contract itself should also go up as the price of the underlying stock goes up.  Unless it's very close to expiration, the option contract should have some ""time value"" in its market price, so, if you want to close your position at this point, earlier then expiration, it will probably be better for you to sell the contract back to the market (for more money and only one commission) than to exercise and then close the stock position (for less money and two commissions). If you want to exercise and then flip the stock back as your exit strategy, you need to be aware of the settlement times.  You probably are not going to instantly have those 100 shares of stock credited to your account, so you may not be able to sell them right away, which could leave you subject to some risk of the price changing.  Alternatively, you could sell the stock short to lock in the price, but you'll have to be sure that your brokerage account is set up to allow that and understand how to do this." "You are likely making an assumption that the ""Short call"" part of the article you refer to isn't making: that you own the underlying stock in the first place. Rather, selling short a call has two primary cases with considerably different risk profiles. When you short-sell (or ""write"") a call option on a stock, your position can either be: covered, which means you already own the underlying stock and will simply need to deliver it if you are assigned, or else uncovered (or naked), which means you do not own the underlying stock. Writing a covered call can be a relatively conservative trade, while writing a naked call (if your broker were to permit such) can be extremely risky. Consider: With an uncovered position, should you be assigned you will be required to buy the underlying at the prevailing price. This is a very real cost — certainly not an opportunity cost. Look a little further in the article you linked, to the Option strategies section, and you will see the covered call mentioned there. That's the kind of trade you describe in your example." Yes, theoretically you can flip the shares you agreed to buy and make a profit, but you're banking on the market behaving in some very precise and potentially unlikely ways.  In practice it's very tricky for you to successfully navigate paying arbitrarily more for a stock than it's currently listed for, and selling it back again for enough to cover the difference.  Yes, the price could drop to $28, but it could just as easily drop to $27.73 (or further) and now you're hurting, before even taking into account the potentially hefty commissions involved. Another way to think about it is to recognize that an option transaction is a bet; the buyer is betting a small amount of money that a stock will move in the direction they expect, the seller is betting a large amount of money that the same stock will not.  One of you has to lose.  And unless you've some reason to be solidly confident in your predictive powers the loser, long term, is quite likely to be you. Now that said, it is possible (particularly when selling puts) to create win-win scenarios for yourself, where you're betting one direction, but you'd be perfectly happy with the alternative(s).   Here's an example.  Suppose, unrelated to the option chain, you've come to the conclusion that you'd be happy paying $28 for BBY.  It's currently (June 2011) at ~$31, so you can't buy it on the open market for a price you'd be happy with.  But you could sell a $28 put, promising to buy it at that price should someone want to sell it (presumably, because the price is now below $28). Either the put expires worthless and you pocket a few bucks and you're basically no worse off because the stock is still overpriced by your estimates, or the option is executed, and you receive 100 shares of BBY at a price you previously decided you were willing to pay.  Even if the list price is now lower, long term you expect the stock to be worth more than $28.  Conceptually, this makes selling a put very similar to being paid to place a limit order to buy the stock itself. Of course, you could be wrong in your estimate (too low, and you now have a position that might not become profitable; too high, and you never get in and instead just watch the stock gain in value), but that is not unique to options - if you're bad at estimating value (which is not to be confused with predicting price movement) you're doomed just about whatever you do. You haven't said why you think you will gain at $41, but the graph never lies. Take it one piece at a time: At $41, your stock will lose a big chunk of value.  Your short calls will expire.  Your puts will gain a bit of value.  The stock's loss outweighs the option gains. My understanding is that all ETF options are American style, meaning they can be exercised before expiration, and so you could do the staggered exercises as you described. "Could have done a [put option](http://en.wikipedia.org/wiki/Put_option) if you wanted to bet against it in another way. It's not technically ""shorting"", but in a layman-shorthand it's the same thing - making money gambling on the ""pessimistic side"" of possibility. You don't actually need to borrow any shares to do that, just find someone who thinks the price at some later date will be higher than you think it will be."