What is the best strategy for after hours trading?
First you will need a plan stating three main points: You will have to decide what criteria you will use to answer these points. You might use Fundamental Analysis to find what to buy and Technical Analysis to decide when to buy and when to sell (your buy and sell triggers). Once you have a Trading Plan in place you would need to find a broker with conditional orders. You can place conditional buy orders to get in a trade (for example if the price moves above or below a target price). You can place conditional stop loss orders if your trade goes against you, and you can also place conditional profit target stops to automatically get out if rises to your desired profit target. You can place one, two or many conditional orders after hours which will enable you to trade without being in front of your screen all day long. I would never trade after hours and I have 30 years of trading experience.  It is a very volatile emotion driven market without a lot of the big players that arbitrage wrong pricing.   If I were you I would simply use limit orders you input while the market is closed.   If you want to get kute you can put in low-ball offers (and vice versa) to see if they get filled in the volatility at market open.  Then check in (when?) when you wake up (or before you go to bed, etc) and revise the limit if not filled.   In other words don't 'trade'.  Know what your company is worth and put in orders that reflect that.
A lot of people here talk about shorting stocks, buying options, and messing around with leveraged ETFs. While these are excellent tools, that offer novel opportunities for the sophisticated investor, Don't mess around with these until you have been in the game for a few years. Even if you can make money consistently right out of the gate, don't do it. Why? Making money isn't your challenge, NOT LOSING money is your challenge. It's hard to measure the scope of the risk you are assuming with these strategies, much less manage it when things head south. So even if you've gotten lucky enough to have figured  out how to make money, you surely haven't learned out how to hold on to it. I am certain that every beginner still hasn't figured out how to comprehend risk and manage losing positions. It's one of those things you only figure out after dealing with it. Stocks (with little to no margin) are a great place to learn how to lose because your risk of losing everything is drastically lower than with the aforementioned tools of the sophisticated investor. Despite what others may say you can make out really well just trading stocks.  That being said, one of my favorite beginner strategies is buying stocks that dip for reasons that don't fundamentally affect the company's ability to make money in the mid term (2 quarters).  Wallstreet loves these plays because it shakes out amateur investors (release bad news, push the stock down shorting it or selling your position, amateurs sell, which you buy at a discount to the 'fair price'.) A good example is Netflix back in 2007. There was a lawsuit because netflix was throttling movie deliveries to high traffic consumers. The stock dropped a good chunk overnight.  A more recent example is petrobras after their huge bond sale and subsequent corruption scandal. A lot of people questioned Petrobras' long-term ability to maintain sufficient liquidity to pay back the loans, but the cashflow and long term projections are more than solid. A year later the stock was pushed further down because a lot of amateur Brazilians invest in Petrobras and they sold while the stock was artificially depressed due to a string of corruption scandals and poor, though temporary, economic conditions. One of my favorite plays back in 2008-2011 was First Solar on the run-up to earnings calls. Analysts would always come out of these meetings downgrading the stock and the forums were full of pikers and pumpers claiming heavy put positions. The stock would go down considerably, but would always pop around earnings. I've made huge returns on this move. Those were the good ole days. Start off just googling financial news and blogs and look for lawsuits and/or scandals. Manufacturing defects or recalls. Starting looking for companies that react predictably to certain events. Plot those events on your chart. If you don't know how to back-test events, learn it.  Google Finance had a tool for that back in the day that was rudimentary but helpful for those starting out. Eventually though, moreso than learning any particular strategy, you should learn these three skills: 1) Tooling: to gather, manipulate, and visualize data on your own.  These days automated trading also seems to be ever more important, even for the small fish. 2) Analytical Thinking learn to spot patterns of the three types:  event based (lawsuits, arbitrage, earnings etc), technical (emas, price action, sup/res), or business-oriented (accounting, strategy, marketing). Don't just listen to what someone else says you should do at any particular moment, critical thinking is essential. 3) Emotions and Attitude: learn how to comprehend risk and manage your trigger finger. Your emotions are like a blade that you must sharpen every day if you want to stay in the game. Disclaimer: I stopped using this strategy in 2011, and moved to a pure technical trading regime. I've been out totally out of the game since 2015. A great way to learn is by watching then doing. I run a very successful technical analysis blog, and the first thing I like to tell my readers is to find a trader online who you can connect with, then watch them trade. I particularly like Adam Hewison, Marketclub.com - This is a great website, and they offer a great deal of eduction for free, in video format. They also offer further video based education through their ino.tv partner which is paid. Here is a link that has their free daily technical analysis based stock market update in video format. Marketclub Daily Stock Market Update Corey Rosenblum, blog.afraidtotrade.com - Corey is a Chartered Market Technician, and runs a fantastic technical analysis blog the focuses on market internals and short term trades. John Lansing, Trending123.com - John is highly successful trader who uses a reliable set of indicators and patterns, and has the most amazing knack for knowing which direction the markets are headed. Many of his members are large account day traders, and you can learn tons from them as well. They have a live daily chat room that is VERY busy. The other option is to get a mentor. Just about any successful trader will be willing to teach someone who is really interested, motivated, and has the time to learn. The next thing to do once you have chosen a route of education is to start virtual trading. There are many platforms available for this, just do some research on Google. You need to develop a trading plan and methodology for dealing with the emotions of trading. While there is no replacement for making real trades, getting some up front practice can help reduce your mistakes, teach you a better traders mindset, and help you with the discipline necessary to be a successful trader. Apparent data-feed issues coming out of NASDAQ in the after hours market. Look at MSFT, AMZN, AAPL, heck even Sears.      Funny thing though, is that you see traces of irregular prices during the active session around 10:20am on stocks like GOOG. "4PM is the market close in NYC, so yes, time looks good.  If ""out of the money,"" they expire worthless.  If ""in the money,"" it depends on your broker's rules, they can exercise the option, and you'll need to have the money to cover on Monday or they can do an exercise/sell, in which case, you'd have two commissions but get your profit.  The broker will need to tell you their exact procedure, I don't believe it's universal." Its hard to write much in those comment boxes, so I'll just make an answer, although its really not a formal answer. Regarding commissions, it costs me $5 per trade, so that's actually $10 per trade ($5 to buy, $5 to sell).  An ETF like TNA ($58 per share currently) fluctuates $1 or $2 per day.  IXC is $40 per share and fluctuates nearly 50 cents per day (a little less).  So to make any decent money per trade would mean a share size of 50 shares TNA which means I need $2900 in cash (TNA is not marginable). If it goes up $1 and I sell, that's $10 for the broker and $40 for me.  I would consider this to be the minimum share size for TNA.  For IXC, 100 shares would cost me $4000 / 2 = $2000 since IXC is marginable.  If IXC goes up 50 cents, that's $10 for the broker and $40 for me.  IXC also pays a decent dividend.  TNA does not.  You'll notice the amount of cash needed to capture these gains is roughly the same. (Actually, to capture daily moves in IXC, you'll need a bit more than $2000 because it doesn't vary quite a full 50 cents each day). At first, I thought you were describing range trading or stock channeling, but those systems require stop losses when the range or channel is broken.  You're now talking about holding forever until you get 1 or 2 points of profit.  Therefore, I wouldn't trade stocks at all.  Stocks could go to zero, ETFs will not.  It seems to me you're looking for a way to generate small, consistent returns and you're not seeking to strike it rich in one trade.  Therefore, buying something that pays a dividend would be a good idea if you plan to hold forever while waiting for your 1 or 2 points. In your system you're also going to have to define when to get back in the trade.  If you buy IXC now at $40 and it goes to $41 and you sell, do you wait for it to come back to $40?  What if it never does?  Are you happy with having only made one trade for $40 profit in your lifetime?  What if it goes up to $45 and then dips to $42, do you buy at $42?  If so, what stops you from eventually buying at the tippy top?  Or even worse, what stops you from feeling even more confident at the top and buying bigger lots?  If it gets to $49, surely it will cover that last buck to $50, right? /sarc What if you bought IXC at $40 and it went down.  Now what?  Do you take up gardening as a hobby while waiting for IXC to come back?  Do you buy more at lower prices and average down?  Do you find other stocks to trade?  If so, how long until you run out of money and you start getting margin calls?  Then you'll be forced to sell at the bottom when you should be buying more. All these systems seem easy, but when you actually get in there and try to use them, you'll find they're not so easy.  Anything that is obvious, won't work anymore.  And even when you find something that is obvious and bet that it stops working, you'll be wrong then too.  The thing is, if you think of it, many others just like you also think of it... therefore it can't work because everyone can't make money in stocks just like everyone at the poker table can't make money.  If you can make 1% or 2% per day on your money, that's actually quite good and not too many people can do that.  Or maybe its better to say, if you can make 2% per trade, and not take a 50% loss per 10 trades, you're doing quite well. If you make $40 per trade profit while working with $2-3k and you do that 50 times per year (50 trades is not a lot in a year), you've doubled your money for the year.  Who does that on a consistent basis?  To expect that kind of performance is just unrealistic.  It much easier to earn $2k with $100k than it is to double $2k in a year.  In stocks, money flows TO those who have it and FROM those who don't. You have to plan for all possibilities, form a system then stick to it, and not take on too much risk or expect big (unrealistic) rewards. Daytrading You make 4 roundtrips in 5 days, that broker labels you a pattern daytrader.  Once you're labeled, its for life at that brokerage.  If you switch to a new broker, the new broker doesn't know your dealings with the old broker, therefore you'll have to establish a new pattern with the new broker in order to be labeled.  If the SEC were to ask, the broker would have to say 'yes' or 'no' concering if you established a pattern of daytrading at that brokerage. Suppose you make the 4 roundtrips and then you make a 5th that triggers the call.  The broker will call you up and say you either need to deposit enough to bring your account to $25k or you need to never make another daytrade at that firm... ever!  That's the only warning you'll ever get.  If you're in violation again, they lock your account to closing positions until you send in funds to bring the balance up to $25k.  All you need to do is have the money hit your account, you can take it right back out again.  Once your account has $25k, you're allowed to trade again.... even if you remove $15k of it that same day.  If you trigger the call again, you have to send the $15k back in, then take it back out. Having the label is not all bad... they give you 4x margin.  So with $25k, you can buy $100k of marginable stock.  I don't know... that could be a bad thing too.  You could get a margin call at the end of the day for owning $100k of stock when you're only allowed to own $50k overnight.  I believe that's a fed call and its a pretty big deal. Well, arbitrage is a simple mean reversion strategy which states that any two similar commodity with some price difference (usually not much)  will converge. So either you can bet on difference in prices in different exchanges or also you can bet on difference in futures value.  For example if current price of stock is 14$ and if futures price is 10$.  Then you can buy one futures contract and short one stock at the market price. This would lock in a profit of 4$ per share. First, accept the fact that you are not going to be able to predict the ups and downs of the market well enough for that to be a viable strategy. In the long run these schemes tend to be losers because it forces you to guess correctly twice (When to get out, when to get back in) and missing either date can cost you. A better strategy to benefit from market volatility: "Your strategy fails to control risk. Your ""inversed crash"" is called a rally. And These kind of things often turn into bigger rallies because of short squeezes, when all the people that are shorting a stock are forced to close their stock because of margin calls - its not that shorts ""scramble"" to close their position, the broker AUTOMATICALLY closes your short positions with market orders and you are stuck with the loss. So no, your ""trick"" is not enough. There are better ways to profit from a bearish outlook." Trading is NOT zero-sum game, it is negative sum actually. In fact all people's money is getting swept by commissions and fees. If you don't have The Plan (which includes minimizing commission losses), you win some (not a lot), then you get big positions, then market crashes, then all your money is gone.  You will start noticing that commissions are real, only when you get market crash. Prey that you get heavy losses (-10% of portfolio) before some (giant) market crash. Getting good lesson by small price is better then high price (-30..50%). Piece of advice. There is small exchanges that do NOT charge you for operations, taking only market spread ($0.01) as commission. They do so because they do not have big population and they trade mostly by using automatic market-makers (which means there is no way to buy 10% of Apple there). "You avoid pattern day trader status by trading e-mini futures through a futures broker. The PDT rules do not apply in the futures markets. Some of the markets that are available include representatives covering the major indices i.e the YM (DJIA), ES (S&P 500) and NQ (Nasdaq 100) and many more markets.  You can take as many round-turn trades as you care to...as many or as few times a day  as you like. E-mini futures contracts trade in sessions with ""transition"" times between sessions. -- Sessions begin Sunday evenings at 6 PM EST and are open through Monday evening at 5 PM EST...The next session begins at 6 pm Monday night running through Tuesday at 5 PM EST...etc...until Friday's session close at 5 PM EST. Just as with stocks, you can either buy first then sell (open and close a position) or short-sell (sell first then cover by buying). You profit (or lose) on a round turn trade in the same manor as you would if trading stocks, options, ETFs etc. The e-mini futures are different than the main futures markets that you may have seen traders working in the ""pits"" in Chicago...E-mini futures are totally electronic (no floor traders) and do not involve any potential delivery of the 'product'...They just require the closing of positions to end a transaction.  A main difference is you need to maintain very little cash in your account in order to trade...$1000 or less per trade, per e-mini contract...You can trade just 1 contract at a time or as many contracts as you have the cash in your account to cover.   ""Settlement"" is immediate upon closing out any position that you may have put on...No waiting for clearing before your next trade.  If you want to hold an e-mini contract position over 2 or more sessions, you need to have about $5000 per contract in your account to cover the minimum margin requirement that comes into play during the transition between sessions... With the e-minis you are speculating on gaining from the difference between when you 'put-on' and ""close-out"" a position in order to profit. For example, if you think the DJIA is about to rise 20 points, you can buy 1 contract. If you were correct in your assessment and sold your contract after the e-mini rose 20 points, you profited $100. (For the DJIA e-mini, each 1 point 'tick' is valued at $5.00)" Assuming you were immersed in math with your CS degree, the book **'A Non-Random Walk Down Wall Street' by Andrew Lo** is a very interesting book about the random walk hypothesis and it's application to financial markets and how efficient markets might not necessarily imply complete randomness.    Lots of higher level concepts in the book but it's an interesting topic if you are trying to branch out into the quant world.  The book isn't very specific towards algorithmic trading but it's good for concept and ideas.  Especially for general finance, that will give you a good run down about markets and the way we tackle modern finance.    **A Random Walk Down Wall Street** (which the book above is named after) by **Burton Malkiel** is also supposed to be a good read and many have suggested reading it before the one I listed above, but there really isn't a need to do so.    For investing specifically, many mention **'The Intelligent Investor' by Benjamin Graham** who is the role model for the infamous Warren Buffet.  It's an older book and really dry and I think kind of out dated but mostly still relevant.  It's more specifically about individual trading rather than markets as a whole or general markets.  It sounds like you want to learn more about markets and finance rather than simply trading or buying stocks.  So I'd stick to the Andrew Lo book first.    ---  Also, since you might not know, it would be a good idea to understand the capital asset pricing model, free cash flow models, and maybe some dividend discount models, the last of which isn't so much relevant but good foundations for your finance knowledge.  They are models using various financial concepts (TVM is almost used in every case) and utilizing them in various ways to model certain concepts.  You'd most likely be immersed in many of these topics by reading a math-oriented Finance book.  Try to stay away from those penny stock trading books, I don't think I need to tell a math major (who is probably much smarter than I am) that you don't need to be engaging in penny stocks, but do your DD and come to a conclusion yourself if you'd like.  I'm not sure what career path you're trying to go down (personal trading, quant firm analyst, regular analyst, etc etc) but it sounds like you have the credentials to be doing quant trading.    ---  Check out www.quantopian.com.  It's a website with a python engine that has all the necessary libraries installed into the website which means you don't have to go through the trouble yourself (and yes, it is fucking trouble--you need a very outdated OS to run one of the libraries).  It has a lot of resources to get into algorithmic trading and you can begin coding immediately.  You'd need to learn a little bit of python to get into this but most of it will be using matplotlib, pandas, or some other library and its own personal syntax. Learning about alpha factors and the Pipeline API is also moderately difficult to get down but entirely possible within a short amount of dedicated time.     Also, if you want to get into algorithmic trading, check out Sentdex on youtube.  He's a python programmer who does a lot of videos on this very topic and has his own tool on quantopian called 'Sentiment Analyzer' (or something like that) which basically quantifies sentiment around any given security using web scrapers to scrape various news and media outlets.  Crazy cool stuff being developed over there and if you're good, you can even be partnered with investors at quantopian and share in profits.    You can also deploy your algorithms through the website onto various trading platforms such as Robinhood and another broker and run your algorithms yourself.    Lots of cool stuff being developed in the finance sector right now.  Modern corporate finance and investment knowledge is built on quite old theorems and insights so expect a lot of things to change in today's world.  ---  With a math degree, finance should be like algebra I back in the day.  You just gotta get familiar with all of the different rules and ideas and concepts.  There isn't that much difficult math until you begin getting into higher level finance and theory, which mostly deals with statistics anyways like covariance and regression and other statistic-related concepts.  Any other math is simple arithmetic. What is a good resource to learn about options trading strategies? Options are a quite advanced investment form, and you'd do well to learn a lot about them before attempting to dive into this fairly illiquid market. Yale's online course in financial markets covers the Options Market and is a good starting point to make sure you've got all the basics. You may be familiar with most of it, but it's a decent refresher on lingo and Black-Scholes. How can I use options to establish some cash flow from long standing investments while minimizing capital gains expenses? This question seems designed to get people to talk about covered calls. Essentially, you sell call contracts: you let people buy things you already have at a price in the future, at their whim. They pay you for this option, though usually not much if the options aren't in the money. You can think of this as trading any return above the call option for a bit of extra cash.  I don't invest with taxable accounts, but there are significant tax consequences for options. Because they expire, there will be turnover in your portfolio, and up front income when you take the sell side. So if you trade in options with close expiration dates, you'll probably end up with a lot of short-term capital gains, which are treated as normal income. One strategy is to trade in broad-based stock index options, which have favorable tax treatments. Some people have abused this though to disguise normal income as capital gains, so it could go away. Obviously the easy approach is to just use a tax advantaged account for options trading. An ETF might also be able to handle the turnover on your behalf, for example VIX is a series of options on S&P500 options. A second strategy I've heard of is buying calls and puts at a given strike price. For example, if you bought Dec '13 calls and puts on SPX @ 115 today, it would cost you about $35 dollars. If the price moves more than 35 dollars away from 115 by DEC '13 (in either direction), you've made a profit. If you reflect on that for a bit, you'll see why VIX is considered a volatility index. I guess I should mention that shorting a stock and buying a put option at the market price are very similar, with the exception that your loss is limited to the price of the option.  Is there ever an instance where options investing is not speculative? The term 'speculative' is not well defined. For many people, the answer is no. It's very easy to just buy put options and wait for prices to fall, or call options and wait for prices to rise. Moreover, the second strategy above essentially gives you similar performance to a stock without paying full price. These all fall under the headline of increasing a risk portfolio rather than decreasing it, which I figure is a decent definition of speculation. On the other hand, there are ways to use options minimize risk rather than increase it. You can buy underwater options as portfolio insurance, if your portfolio drops below a certain amount, you still have the right to sell it at a higher one. And the Case-Schiller index is run in part, on the hopes that one day there might be a thriving market for real estate options (or futures). When you buy a home or lend money to someone to buy one, you could buy regional Case-Schiller options to protect you if the regional market tanks. But in all of these cases, it's required for someone else to take the opposite trade. Risk isn't reduced, it's traded around. So technically, there is a speculative element to these as well. I think the proper question here is whether speculation is present, but whether speculation can be put to good ends. Without speculators, the already very thin market for options would shrivel faster. the strategy is tested all the way to 97. how is the continuous series backadjusted? the emini is rolledover and Ratio back adjusted to the 2nd nearest contract, 9 days prior to expiration. since it is an intraday trade, the discrepancy to the real thing should be next to irrelevant. but comparing it to the spx could make it interesting.  what would be a good format to present the results ? jpeg? pdf ? "Your plan already answers your own question in the best possible way: If you want to be able to make the most possible profit from a large downward move in a stock (in this case, a stock that tracks gold), with a limited, defined risk if there is an upward move, the optimal strategy is to buy a put option.  There are a few Exchange Traded Funds (ETFs) that track the price of gold.  think of them as stocks that behave like gold, essentially.  Two good examples that have options are GLD and IAU. (When you talk about gold, you'll hear a lot about futures.  Forget them, for now.  They do the same essential thing for your purposes, but introduce more complexity than you need.) The way to profit from a downward move without protection against an upward move is by shorting the stock.   Shorting stock is like the opposite of buying it.    You make the amount of money the stock goes down by, or lose the amount it goes up by.   But, since stocks can go up by an infinite amount, your possible loss is unlimited. If you want to profit on a large downward move without an unlimited loss if you're wrong and it goes up, you need something that makes money as the stock drops, but can only lose so much if it goes up.   (If you want to be guaranteed to lose nothing, your best investment option is buying US Treasuries, and you're technically still exposed to the risk that US defaults on its debt, although if you're a US resident, you'll likely have bigger problems than your portfolio in that situation.) Buying a put option has the exact asymmetrical exposure you want.   You pay a limited premium to buy it, and at expiration you essentially make the full amount that the stock has declined below the strike price, less what you paid for the option.   That last part is important - because you pay a premium for the option, if it's down just a little, you might still lose some or all of what you paid for it, which is what you give up in exchange for it limiting your maximum loss. But wait, you might say.  When I buy an option, I can lose all of my money, cant I?  Yes, you can.    Here's the key to understanding the way options limit risk as compared to the corresponding way to get ""normal"" exposure through getting long, or in your case, short, the stock: If you use the number of options that represent the number of shares you would have bought, you will have much, much less total money at risk. If you spend the same ""bag 'o cash"" on options as you would have spent on stock, you will have exposure to way more shares, and have the same amount of money at risk as if you bought the stock, but will be much more likely to lose it. The first way limits the total money at risk for a similar level of exposure; the second way gets you exposure to a much larger amount of the stock for the same money, increasing your risk. So the best answer to your described need is already in the question:   Buy a put.  I'd probably look at GLD to buy it on, simply because it's generally a little more liquid than IAU. And if you're new to options, consider the following: ""Paper trade"" first.  Either just keep track of fake buys and sells on a spreadsheet, or use one of the many online services where you can track investments - they don't know or care if they're real or not. Check out www.888options.com.  They are an excellent learning resource that isn't trying to sell you anything - their only reason to exist is to promote options education.   If you do put on a trade, don't forget that the most frustrating pitfall with buying options is this:  You can be basically right, and still lose some or all of what you invest.  This happens two ways, so think about them both before you trade: If the stock goes in the direction you think, but not enough to make back your premium, you can still lose.  So you need to make sure you know how far down the stock has to be to make back your premium.  At expiration, it's simple: You need it to be below the strike price by more than what you paid for the option. With options, timing is everything.  If the stock goes down a ton, or even to zero - free gold! - but only after your option expires, you were essentially right, but lose all your money.  So, while you don't want to buy an option that's longer than you need, since the premium is higher, if you're not sure if an expiration is long enough out, it isn't - you need the next one. EDIT to address update: (I'm not sure ""not long enough"" was the problem here, but...) If the question is just how to ensure there is a limited, defined amount you can lose (even if you want the possible loss to be much less than you can potentially make, the put strategy described already does that - if the stock you use is at $100, and you buy a put with a 100 strike for $5, you can make up to $95.   (This occurs if the stock goes to zero, meaning you could buy it for nothing, and sell it for $100, netting $95 after the $5 you paid).   But you can only lose $5. So the put strategy covers you. If the goal is to have no real risk of loss, there's no way to have any real gain above what's sometimes called the ""risk-free-rate"".  For simplicity's sake, think of that as what you'd get from US treasuries, as mentioned above. If the goal is to make money whether the stock (or gold) goes either up or down, that's possible, but note that you still have (a fairly high) risk of loss, which occurs if it fails to move either up or down by enough.  That strategy, in its most common form, is called a straddle, which basically means you buy a call and a put with the same strike price.  Using the same $100 example, you could buy the 100-strike calls for $5, and the 100-strike puts for $5.  Now you've spent $10 total, and you make money if the stock is up or down by more than $10 at expiration (over 110, or under 90).   But if it's between 90 and 100, you lose money, as one of your options will be worthless, and the other is worth less than the $10 total you paid for them both." "I read the book, and I'm willing to believe you'd have a good chance of beating the market with this strategy - it is a reasonable, rational, and mechanical investment discipline. I doubt it's overplayed and overused to the point that it won't ever work again. But only IF you stick to it, and doing so would be very hard (behaviorally). Which is probably why it isn't overplayed and overused already. This strategy makes you place trades in companies you often won't have heard of, with volatile prices. The best way to use the strategy would be to try to get it automated somehow and avoid looking at the individual stocks, I bet, to take your behavior out of it. There may well be some risk factors in this strategy that you don't have in an S&P 500 fund, and those could explain some of the higher returns; for example, a basket of sketchier companies could be more vulnerable to economic events. The strategy won't beat the market every year, either, so that can test your behavior. Strategies tend to work and then stop working (as the book even mentions). This is related to  whether other investors are piling in to the strategy and pushing up prices, in part.  But also, outside events can just happen to line up poorly for a given strategy; for example a bunch of the ""fundamental index"" ETFs that looked at dividend yield launched right before all the high-dividend financials cratered. Investing in high-dividend stocks probably is and was a reasonable strategy in general, but it wasn't a great strategy for a couple years there. Anytime you don't buy the whole market, you risk both positive and negative deviations from it. Here's maybe a bigger-picture point, though. I happen to think ""beating the market"" is a big old distraction for individual investors; what you really want is predictable, adequate returns, who cares if the market returns 20% as long as your returns are adequate, and who cares if you beat the market by 5% if the market cratered 40%. So I'm not a huge fan of investment books that are structured around the topic of beating the market. Whether it's index fund advocates saying ""you can't beat the market so buy the index"" or Greenblatt saying ""here's how to beat the market with this strategy,"" it's still all about beating the market. And to me, beating the market is just irrelevant. Nobody ever bought their food in retirement because they did or did not beat the market. To me, beating the market is a game for the kind of actively-managed mutual fund that has a 90%-plus R-squared correlation with the index; often called an ""index hugger,"" these funds are just trying to eke out a little bit better result than the market, and often get a little bit worse result, and overall are a lot of effort with no purpose. Just get the index fund rather than these. If you're getting active management involved, I'd rather see a big deviation from the index, and I'd like that deviation to be related to risk control: hedging, or pulling back to cash when valuations get rich, or avoiding companies without a ""moat"" and margin of safety, or whatever kind of risk control, but something. In a fund like this, you aren't trying to beat the market, you're trying to increase the chances of adequate returns - you're optimizing for predictability. I'm not sure the magic formula is the best way to do that, focused as it is on beating the market rather than on risk control. Sorry for the extra digression but I hope I answered the question a bit, too. ;-)"