Comparison between buying a stock and selling a naked put
I sell a put for a strike price at the market. The stock rises $50 over the next couple months. I've gotten the premium, but lost the rest of the potential gain, yet had the downside risk the whole time.  There's no free lunch.  Edit - you can use a BS (Black-Scholes) calculator to create your own back testing. The calculator shows a 1% interest rate, 2% yield, and 15% volatility produce a put price almost identical to the pricing I see for S&P (the SPY ETF, specifically) $205 put. No answer here, including mine, gave any reference to a study. If one exists, it will almost certainly be on an index, not individual stocks. Note that Jack's answer referencing PUTX does exactly that. The SPY ETF and it put options. My suggestion here would, in theory, let you analyze this strategy for individual stock options as well.  For SPY - With SPY at 204.40, this is the Put you'd look at -  12 times the premium is $33.36 or 16% the current price. The next part of the exercise is to see how the monthly ups and downs impact this return. A drop to $201 wipes out that month's premium.  It happens that it now March 18th, and despite a bad start to the year, we are at break-even YTD. A peek back shows In Dec you picked up $2.87 premium, (1.4% the current price then) but in Jan, it closed for a loss of $12. Ouch. Now, if you started in January, you'd have picked up 2 month's premiums and today or Monday sell the 3rd. You'd have 2.8% profit so far, vs the S&P break even.  Last, for now, when selling a naked put, you have to put up margin money. Not sure how much, but I use percent of the value of underlying stock to calculate returns. That choice is debatable, it just keeps percents clean. Else you put up no money and have infinite return. "Yes, of course there have been studies on this.  This is no more than a question about whether the options are properly priced. (If properly priced, then your strategy will not make money on average before transaction costs and will lose once transaction costs are included.  If you could make money using your strategy, on average, then the market should - and generally will - make an adjustment in the option price to compensate.) The most famous studies on this were conducted by Black and Scholes and then by Merton. This work won the Nobel Prize in 1995. Although the Black-Scholes (or Black-Scholes-Merton) equation is so well known now that people may forget it, they didn't just sit down one day and write and equation that they thought was cool. They actually derived the equation based on market factors. Beyond this ""pioneering"" work, you've got at least two branches of study.  Academics have continued to study option pricing, including but not limited to revisions to the original Black-Scholes model, and hedge funds / large trading house have ""quants"" looking at this stuff all of the time.  The former, you could look up if you want. The latter will never see the light of day because it's proprietary. If you want specific references, I think that any textbook for a quantitative finance class would be a fine place to start.  I wouldn't be surprised if you actually find your strategy as part of a homework problem. This is not to say, by the way, that I don't think you can make money with this type of trade, but your strategy will need to include more information than you've outlined here.  Choosing which information and getting your hands on it in a timely manner will be the key." Why do all this work yourself? Pay a modest price to have a professional do this for you. Look at the tickers PUTX, PUTW. Option prices are computed by determining the cost of obtaining the option returns using a strategy that trades the underlying asset continuously.  It sounds like what you are describing is rapidly trading the option in order to obtain returns similar to those of the stock.  The equality goes both ways.   If the option is appropriately priced, then a strategy that replicates stock returns using the option will cost the same as buying the stock. Because you can't trade continuously, you won't actually be able to replicate the stock return, and it may seem like you are making arbitrage profit (puts may seem abnormally expensive), but you do so by bearing tail risk (i.e., selling puts loses more money than owning the associated stock if an unusually bad event occurs).
"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." To add to @Victor 's answer; if you are entering a market order, and not a limit order (where you set the price you want to buy or sell at), then the Ask price is what you can expect to pay to purchase shares of stock in a long position and the Bid price is what you can expect to receive when you sell stock you own in a long position. "I think the question, as worded, has some incorrect assumptions built into it, but let me try to hit the key answers that I think might help: Your broker can't really do anything here.   Your broker doesn't own the calls you sold, and can't elect to exercise someone else's calls. Your broker can take action to liquidate positions when you are in margin calls, but the scenario you describe wouldn't generate them:  If you are long stock, and short calls, the calls are covered, and have no margin requirement.  The stock is the only collateral you need, and you can have the position on in a cash (non-margin) account.   So, assuming you haven't bought other things on margin that have gone south and are generating calls, your broker has no right to do anything to you. If you're wondering about the ""other guy"", meaning the person who is long the calls that you are short, they are the one who can impact you, by exercising their right to buy the stock from you.  In that scenario, you make $21, your maximum possible return (since you bought the stock at $100, collected $1 premium, and sold it for $120.  But they usually won't do that before expiration, and they pretty definitely won't here.  The reason they usually won't is that most options trade above their intrinsic value (the amount that they're in the money).    In your example, the options aren't in the money at all.   The stock is trading at 120, and the option gives the owner the right to buy at 120.* Put another way, exercising the option lets the owner buy the stock for the exact same price anyone with no options can in the market.  So, if the call has any value whatsoever, exercising it is irrational; the owner would be better off selling the call and buying the stock in the market." Today SPY (The S&P ETF) trades at $128. The option to buy at $140 (this is a Jan '13 call) trades for $5.  I buy the call, for $500 as they trade in 100 lots.  The S&P skyrockets to 1500 and SPY to $150. The call trades for $11, as it still has a month or two before expiring, so I sell it, and get $1100. The S&P rose 17%, but I doubled my money. If it 'only' rose 9%, to less than $140, I'd lose my investment. No, I don't need to buy the SPY I can sell the call any time before expiration. In fact, most options are not exercised, they are sold between purchase and expiration date. The difference is ordinary income. If the price drops and you sell for exactly what you paid, you have an income of D and a capital loss of D which usually cancel each other, but not always. For example, if you already have over $3000 in losses, this loss won't help you, it will carry forward.  The above changes a bit if you hold the stock for 2 years after the beginning of the purchase period. If sold between your purchase price and fair market the day you bought, the gain is only the difference, no gain to fair market + loss.   Pretty convoluted. Your company should have provided you with a brief FAQ / Q&A to explain this.  My friends at Fairmark have an article that explains the ESPP process clearly, Tax Reporting for Qualifying Dispositions of ESPP Shares. When you buy a stock, the worst case scenario is that it drops to 0.  Therefore, the most you can lose when buying a stock is 100% of your investment. When you short a stock, however, there's no limit on how high the stock can go.  If you short a stock at 10, and it goes up to 30, then you've lost 200% on your investment.  Therefore shorting stocks is riskier than buying stocks, since you can lose more than 100% of your investment when shorting. because the price might go up, but it will never be as big of a change as a regular price drop i suppose... That is not true.  Stocks can sometimes go up significantly (50-100% or more) in a very short amount of time on a positive news release (such as an earnings or a buyout announcement).  A famous example occurred in 2008, when Volkswagen stock quintupled (went up 400%) in less than 2 days on some corporate news: Porsche, for some reason, wants to control Volkswagen, and by building up its stake has driven up the price. Hedge funds, figuring the share price would fall as soon as Porsche got control and stopped buying, sold a lot of VW shares short. Then last weekend, Porsche disclosed that it owned 42.6 percent of the stock and had acquired options for another 31.5 percent. It said it wanted to go to 75 percent. The result: instant short-squeeze. The German state of Lower Saxony owns a 20 percent stake in VW, which it said it would not sell. That left precious few shares available for anyone else. The shorts scrambled to cover, and the price leaped from about €200, or about $265, to above €1,000. Here's a simple example for a put, from both sides. Assume XYZ stock trades at $200 right now.  Let's say John writes a $190 out of the money put on XYZ stock and sells this put to Abby for the premium, which is say $5. Assume the strike date, or date of settlement, is 6 months from now.  Thus Abby is long one put option and John is short one put option (the writer of the option is short the option). On settlement date, let's assume two different scenarios: (1) If the price of the stock decreases by $50, then the put that Abby bought is 'in the money'. Abby's profit can be calculated as being strike price 190 - current stock price 150 - premium paid 5 = $35 So not including any transaction fees, that is a $35 dollar return on a $5 investment. (2) If the price of the stock increases by $50, then the put that Abby bought is worthless and her loss was 100%, or her entire $5 premium.  For John, he made $5 in 6 months (in reality you need collateral and good credit to be able to write sizable option positions). In order to compare the two, you need to compare your entire portfolio, which is not just how much money you have, but how much stock. In both scenarios, you start with (at least, but let's assume) £20 and 0 stock. In your scenario, you buy 10 shares, leaving you with £0 and 10 shares. You then sell it at £1.50/share to cut your losses, leaving you with £15 and 0 shares. That concludes the first transaction with a net loss of £5. In a second transaction, you then buy 10 shares again at £1/share, leaving you with £5 and 10 shares. You are still down £15 from the start, but you also still have 10 shares. Any further profit or loss depends on what you can get for those 10 shares in the future. In a short sale, you borrow 10 shares and sell them, leaving you with £40 (your initial £20 plus what you just made on the short sale) and -10 shares of stock. At the end of the contract, you must buy 10 shares to return them; you are able to do so at £1.50/share, leaving you with £25 and 0 shares. At this point, your exposure to the stock is complete, and you have a net gain of £5. My instinct says that there should be no difference. Your instincts are right. Your understanding of math is not so much. You sold $100K at the current price of 7500000RUB, but ended up buying at 3500000, you earned 3500000RUB. That's 100% in USD (50% in RUB). You bought 7500000RUB for the current price of $100K, but sold later for $200K. You earned $100K (100% in USD), which at that time was equal 3500000RUB. You earned 3500000RUB. That's 50% in RUB. So, as your instincts were saying - no difference. The reason percentages are different is because you're coming from different angles. For the first case your currency is RUB, for the second case your currency is USD, and in both cases you earned 100%. If you use the same currency for your calculations, percentages change, but the bottom line - is the same. Many of the Bitcoin exchanges mimic stock exchanges, though they're much more rudimentary offering only simple buy/sell/cancel orders.  It's fairly normal for retail stock brokerage accounts to allow other sorts of more complex orders, where once a certain criteria is met, (the price falls below some $ threshold, or has a movement greater than some %) then your order is executed.  The space between the current buy order and the current sell order is the bid/ask spread, it's not really about timing.  Person X will buy at $100, person Y will sell at $102.  If both had a price set at $101, they would just transact.  Both parties think they can do a little bit better than the current offer.  The width of the bid/ask spread is not universal by any means.  The current highest buy order and the current lowest sell order, are both the current price.  The current quoted market price is generally the price of the last transaction, whether it's buy or sell. "SELL -10 VERTICAL $IYR 100 AUG 09 32/34 CALL @.80 LMT 1) we are talking about options, these are a derivative product whose price is based on 6 variables. 2) options allow you to create risk out of thin air, and those risks come with shapes, and the only limit is your imagination (and how much your margin/borrowing costs are). Whereas a simple asset like the shares for $IYR only has a linear risk profile. stock goes up, you make money, stock goes down, you lose money, and that risk graph looks linear. a ""vertical"" has a nonlinear risk profile 3) a vertical is a type of ""spread"" that requires holding options that expire at the same time, but at different strike prices. 3b) This particular KIND of vertical is called a bear call spread (BCS). Since you are bearish (this makes money if the stock goes down, or stays in a very specific range) but are using calls which are a bullish options product. 4) -10 means you are selling the vertical. +10 means you are buying the vertical. A ""long"" vertical is initiated by buying an option closer to the money, and selling an option at a higher strike price. This would be +X A ""short"" vertical is initiated by selling an option closer to the money and buying an option at a higher strike price. The quantity would be -X 5) 32/34 stands for the strike prices. so you would be selling 10 call options at the 32 strike price, and buying 10 call options at the 34 strike price, both options expire in August 6) LMT stands for limit order, and $.80 is the limit order price that is desired. OPENING a vertical spread requires knowledge of options as well as how to send orders. MANAGING a vertical requires even more finesse, as you can ""leg-in"" and ""leg-out"" of spreads, without sending the entire order to the exchange floor at once. There is much to learn." "A covered call risks the disparity between the purchase price and the potential forced or ""called"" sale price less the premium received. So buy a stock for $10.00 believing it will drop you or not rise above $14.00 for a given period of days. You sell a call for a $1.00 agreeing to sell your stock for $14.00 and your wrong...the stock rises and at 14.00 or above during the option period  the person who paid you the $1.00 premium gets the stock for a net effective price of $15.00. You have a gain of 5$. Your hypothecated loss is unlimited in that the stock could go to $1mil a share. That loss is an opportunity loss you still had a modest profit in actual $. The naked call is a different beast. you get the 1.00 in commission to sell a stock you don't own but must pay for that right. so lets say you net .75 in commission per share after your sell the option. as long as the stock trades below $14.00 during the period of the option you sold your golden. It rises above the strike price you must now buy that stock at market to fill the order when the counter party choses to exercise the option which results in a REAL loss of 100% of the stocks market price less the .75 a share you made.   in the scenarios a 1000 shares that for up $30.00 a share over the strike price make you $5,000 in a covered call and lose you $29,250 in a naked call.Naked calls are speculative. Covered calls are strategic." "Investors are ""forever"" comparing the prices of stocks to other stocks. As others have pointed out, this is done faster and more frequently nowadays with high-speed computer programs. There may be no ""fresh"" news on stock A, but if there is fresh news on stock B (as there usually is), the news on B affects the COMPARISON with stock A. That could be what causes trading in stock A that has ""no news.""" I doubt that this exists, but it could theoretically. After all, a share is kind of an option to a company's future success, and so a call is already a second level on indirection. The better approach would be to 'create your own Put-Puts', by investing less money (A) in the Put you wanted to invest into, and put the smaller rest (B) in the share itself or a Call. That way, if the original Put is successful, at max (B) is lost, and if it is unsuccessful, the loss on (A) is covered by a gain on (B). Potentially, if you do the math, you can reach a mathematical equivalent situation to a Put-Put by buying the right amount and kind of Calls. However, we know already that buying a Put and a Call is a poor strategy, so that would mean a Put-Put would also be a poor strategy. If you're into math, do this thought experiment: Consider the outcome X of a random walk process (a stock doesn't behave this way, but for understanding the question you asked, this is useful): On the first day, X=some integer X1. On each subsequent day, X goes up or down by 1 with probability 1/2. Let's think of buying a call option on X. A European option with a strike price of S that expires on day N, if held until that day and then exercised if profitable, would yield a value Y = min(X[N]-S, 0). This has an expected value E[Y] that you could actually calculate. (should be related to the binomial distribution, but my probability & statistics hat isn't working too well today) The market value V[k] of that option on day #k, where 1 < k < N, should be V[k] = E[Y]|X[k], which you can also actually calculate. On day #N, V[N] = Y. (the value is known) An American option, if held until day #k and then exercised if profitable, would yield a value Y[k] = min(X[k]-S, 0).  For the moment, forget about selling the option on the market. (so, the choices are either exercise it on some day #k, or letting it expire) Let's say it's day k=N-1.  If X[N-1] >= S+1 (in the money), then you have two choices: exercise today, or exercise tomorrow if profitable. The expected value is the same. (Both are equal to X[N-1]-S). So you might as well exercise it and make use of your money elsewhere. If X[N-1] <= S-1 (out of the money), the expected value is 0, whether you exercise today, when you know it's worthless, or if you wait until tomorrow, when the best case is if X[N-1]=S-1 and X[N] goes up to S, so the option is still worthless. But if X[N-1] = S (at the money), here's where it gets interesting. If you exercise today, it's worth 0. If wait until tomorrow, there's a 1/2 chance it's worth 0 (X[N]=S-1), and a 1/2 chance it's worth 1 (X[N]=S+1). Aha! So the expected value is 1/2. Therefore you should wait until tomorrow. Now let's say it's day k=N-2.  Similar situation, but more choices: If X[N-2] >= S+2, you can either sell it today, in which case you know the value = X[N-2]-S, or you can wait until tomorrow, when the expected value is also X[N-2]-S. Again, you might as well exercise it now. If X[N-2] <= S-2, you know the option is worthless. If X[N-2] = S-1, it's worth 0 today, whereas if you wait until tomorrow, it's either worth an expected value of 1/2 if it goes up (X[N-1]=S), or 0 if it goes down, for a net expected value of 1/4, so you should wait. If X[N-2] = S, it's worth 0 today, whereas tomorrow it's either worth an expected value of 1 if it goes up, or 0 if it goes down -> net expected value of 1/2, so you should wait. If X[N-2] = S+1, it's worth 1 today, whereas tomorrow it's either worth an expected value of 2 if it goes up, or 1/2 if it goes down (X[N-1]=S) -> net expected value of 1.25, so you should wait. If it's day k=N-3, and X[N-3] >= S+3 then E[Y] = X[N-3]-S and you should exercise it now; or if X[N-3] <= S-3 then E[Y]=0.  But if X[N-3] = S+2 then there's an expected value E[Y] of (3+1.25)/2 = 2.125 if you wait until tomorrow, vs. exercising it now with a value of 2; if X[N-3] = S+1 then E[Y] = (2+0.5)/2 = 1.25, vs. exercise value of 1; if X[N-3] = S then E[Y] = (1+0.5)/2 = 0.75 vs. exercise value of 0; if X[N-3] = S-1 then E[Y] = (0.5 + 0)/2 = 0.25, vs. exercise value of 0; if X[N-3] = S-2 then E[Y] = (0.25 + 0)/2 = 0.125, vs. exercise value of 0. (In all 5 cases, wait until tomorrow.) You can keep this up; the recursion formula is E[Y]|X[k]=S+d = {(E[Y]|X[k+1]=S+d+1)/2 + (E[Y]|X[k+1]=S+d-1) for N-k > d > -(N-k), when you should wait and see} or {0 for d <= -(N-k), when it doesn't matter and the option is worthless} or {d for d >= N-k, when you should exercise the option now}. The market value of the option on day #k should be the same as the expected value to someone who can either exercise it or wait. It should be possible to show that the expected value of an American option on X is greater than the expected value of a European option on X. The intuitive reason is that if the option is in the money by a large enough amount that it is not possible to be out of the money, the option should be exercised early  (or sold), something a European option doesn't allow, whereas if it is nearly at the money, the option should be held, whereas if it is out of the money by a large enough amount that it is not possible to be in the money, the option is definitely worthless. As far as real securities go, they're not random walks (or at least, the probabilities are time-varying and more complex), but there should be analogous situations. And if there's ever a high probability a stock will go down, it's time to exercise/sell an in-the-money American option, whereas you can't do that with a European option. edit: ...what do you know: the computation I gave above for the random walk isn't too different conceptually from the Binomial options pricing model.