How to measure systematic risk of a stock?
"Beta is the correct answer.  It is THE measure of the risk relationship of a stock with the broad market. R squared is incorrect unless you mean something very odd by ""co-efficiency.""  A stock that goes up each time the market goes down has very low co-efficiency (negative risk as you have defined it) but very high R squared.  A stock that goes the same direction as the market but twice as far (with a lot of noise) has a very low R squared but contains a lot of market risk.  A stock that always goes in the same direction as the market but only a 100th as far is very safe but has a very high R squared. You can calculate beta using ""slope"" in excel or doing a regression, but the easiest thing is just to look up the beta in yahoo finance or elsewhere.  You don't need to calculate it for yourself normally."
"Certainly no one knows in advance how much a stock is going to swing around. However, there are measures of how much it has swung around in the past, and there are people who will estimate the probability. First of all, there's a measure of an individual stock's volatility, commonly referred to as ""beta"". A stock with a beta of 1 tends to rise and fall about as much as the market at large. A stock with a beta of 2, in the meantime, would rise 10% when the market is up 5%. These are, of course, historical averages. See Wikipedia: http://en.wikipedia.org/wiki/Beta_(finance) Secondly, you can get an implied measure of volatility expectations by looking at options pricing. If a stock is particularly volatile, the chance of a big price move will be baked into the price of the stock options. (Note also that other things affect options pricing, such as the time value of money.) For an options-based measure of the volatility of the whole market, see the Volatility Index aka the ""Fear Gauge"", VIX.  Wikipedia: http://en.wikipedia.org/wiki/VIX Chart: http://finance.yahoo.com/q?s=%5EVIX Looking at individual stocks as a group (and there's an oxymoron for you), individual stocks are definitely much more likely to have big moves than the market. Besides Netflix, consider the BP oil spill, or the Tokyo Electric Power Company's Fukushima incident (yow!). I don't have any detailed statistics on quantitatively how much, mind you, but in application, a standard piece of advice says not to put more than 5% of your portfolio in a single company's stock. Diversification protects you. (Alternatively, if you're trying to play Mr. Sophisticated Stock-Picker instead of just buying an index fund, you can also buy insurance through stock options: hedging your bets. Naturally, this will eat up part of your returns if your pick was a good one)." You won't be able to know the trading activity in a timely, actionable method in most cases. The exception is if the investor (individual, fund, holding company, non-profit foundation, etc) is a large shareholder of a specific company and therefore required to file their intentions to buy or sell with the SEC. The threshold for this is usually if they own 5% or greater of the outstanding shares. You can, however, get a sense of the holdings for some of the entities you mention with some sleuthing. Publicly-Traded Holding Companies Since you mention Warren Buffett, Berkshire Hathaway is an example of this. Publicly traded companies (that are traded on a US-based exchange) have to file numerous reports with the SEC. Of these, you should review their Annual Report and monitor all filings on the SEC's website. Here's the link to the Berkshire Hathaway profile. Private Foundations Harvard and Yale have private, non-profit foundations. The first place to look would be at the Form 990 filings each is required to file with the IRS. Two sources for these filings are GuideStar.org and the FoundationCenter.org. Keep in mind that if the private foundation is a large enough shareholder in a specific company, they, too, will be required to file their intentions to buy or sell shares in that company. Private Individuals Unless the individual publicly releases their current holdings, the only insight you may get is what they say publicly or have to disclose — again, if they are a major shareholder. "There are a number of ways to measure such things and they are generally called ""sentiment indicators"".  The ones that I have seen ""work"", in the sense that they show relatively high readings near market tops and relatively low readings near market bottoms.  The problem is that there are no thresholds that work consistently.  For example, at one market top a sentiment indicator may read 62.  At the next market top that same indicator might read 55.  So what threshold do you use next time?  Maybe the top will come at 53, or maybe it will not come until 65. There was a time when I could have listed examples for you with the names of the indicators and what they signaled and when.  But I gave up on such things years ago after seeing such wide variation.  I have been at this a long time (30+ years), and I have not found anything that works as well as we would like at identifying a top in real time.  The best I have found (although it does give false signals) is a drop in price coupled with a bearish divergence in breadth.  The latter is described in ""Stan Weinstein's Secrets For Profiting in Bull and Bear Markets"". Market bottoms are a little less difficult to identify in real time.  One thing I would suggest if you think that there is some way to get a significant edge in investing, is to look at the results of Mark Hulbert's monitoring of newsletters.  Virtually all of them rise and fall with the market and almost none are able to beat buy and hold of the Wilshire 5000 over the long term." "the ""how"" all depends on your level of computer savvy. Are you an Excel spreadsheet user or can you write in programming languages such as python? Either approach have math functions that make the calculation of ROI and Volatility trivial. If you're a python coder, then look up ""pandas"" (http://pandas.pydata.org/) - it handles a lot of the book-keeping and downloading of end of day equities data. With a dozen lines of code, you can compute ROI and volatility." Set your xirr formula to a very tall column, leaving lots of empty rows for future additions. In column C, instead of hardcoding the value, use a formula that tests if it's the current bottom entry, like this: =IF(ISBLANK(A7),-C6, C6) If the next row has no date entered (yet), then this is the latest value, and make it negative. Now, to digress a bit, there are several ways to measure returns. I feel XIRR is good for individual positions, like holding a stock, maybe buying more via DRIP, etc. For the whole portfolio it stinks. XIRR is greatly affected by timing of cash flows. Steady deposits and no withdrawals dramatically skew the return lower. And the opposite is true for steady withdrawals. I prefer to use TWRR (aka TWIRR). Time Weighted Rate of Return. The word 'time' is confusing, because it's the opposite. TWRR is agnostic to timing of cashflows. I have a sample Excel spreadsheet that you're welcome to steal from: http://moosiefinance.com/static/models/spreadsheets.html (it's the top entry in the list). Some people prefer XIRR. TWRR allows an apples-to-apples comparison with indexes and funds. Imagine twin brothers. They both invest in the exact same ideas, but the amount of cash deployed into these ideas is different, solely because one brother gets his salary bonus annually, in January, and the other brother gets no bonus, but has a higher bi-weekly salary to compensate. With TWRR, their percent returns will be identical. With XIRR they will be very different. TWRR separates out investing acumen from the happenstance timing of when you get your money to deposit, and when you retire, when you choose to take withdrawals. Something to think about, if you like. You might find this website interesting, too: http://www.dailyvest.com/ The portion of a stock movement not correlated with stocks in general is called Alpha. I don't know of any online tools to graph alpha. Keep in mind that a company like Apple is so huge right now that any properly weighted index will have to correlate with it to some degree. "For a retail investor who isn't a Physics or Math major, the ""Beta"" of the stock is probably the best way to quantify risk.  Examples: A Beta of 1 means that a stock moves in line with the market. Over 1 means that you would expect the stock to move up or down faster than the market as a whole. Under 1 means that you would expect the stock to move slower than the market as a whole." "The question is: how do you quantify investment risk? As Michael S says, one approach is to treat investment returns as a random variable. Bill Goetzmann (Yale finance professor) told me that if you accept that markets are efficient or that the price of an asset reflects it's underlying value, then changes in price represent changes in value, so standard deviation naturally becomes the appropriate measure for riskiness of an asset. Essentially, the more volatile an asset, the riskier it is. There is another school of thought that comes from Ben Graham and Warren Buffett, which says that volatility is not inherently risky. Rather, risk should be defined as the permanent loss of capital, so the riskiness of an asset is the probability of a permanent loss of capital invested.  This is easy to do in casino games, based on basic probability such as   roulette or slots. But what has been done with the various kinds of   investment risks? My point is saying that certain bonds are ""low risk""   isn't good enough; I'd like some numbers--or at least a range of   numbers--and therefore one could calculate expected payoff (in the   statistics sense). Or can it not be done--and if not, why not? Investing is more art than science. In theory, a Triple-A bond rating means the asset is riskless or nearly riskless, but we saw that this was obviously wrong since several of the AAA mortgage backed securities (MBS) went under prior to the recent US recession. More recently, the current threat of default suggests that bond ratings are not entirely accurate, since US Treasuries are considered riskless assets.  Investors often use bond ratings to evaluate investments - a bond is considered investment grade if it's BBB- or higher. To adequately price bonds and evaluate risk, there are too many factors to simply refer to a chart because things like the issuer, credit quality, liquidity risk, systematic risk, and unsystematic risk all play a factor.  Another factor you have to consider is the overall portfolio. Markowitz showed that adding a riskier asset can actually lower the overall risk of a portfolio because of diversification. This is all under the assumption that risk = variance, which I think is bunk.  I'm aware that Wall Street is nothing like roulette, but then again   there must be some math and heavy economics behind calculating risk   for individual investors. This is, after all, what ""quants"" are paid   to do, in part. Is it all voodoo? I suspect some of it is, but not all   of it. Quants are often involved in high frequency trading as well, but that's another note. There are complicated risk management products, such as the Aladdin system by BlackRock, which incorporate modern portfolio theory (Markowitz, Fama, Sharpe, Samuelson, etc) and financial formulas to manage risk.  Crouhy's Risk Management covers some of the concepts applied.  I also tend to think that when people point to the last x number of   years of stock market performance, that is of less value than they   expect. Even going back to 1900 provides ""only"" 110 years of data, and   in my view, complex systems need more data than those 40,500 data   points. 10,000 years' worth of data, ok, but not 110. Any books or articles that address these issues, or your own informed   views, would be helfpul. I fully agree with you here. A lot of work is done in the Santa Fe Institute to study ""complex adaptive systems,"" and we don't have any big, clear theory as of yet. Conventional risk management is based on the ideas of modern portfolio theory, but a lot of that is seen to be wrong. Behavioral finance is introducing new ideas on how investors behave and why the old models are wrong, which is why I cannot suggest you study risk management and risk models because I and many skilled investors consider them to be largely wrong. There are many good books on investing, the best of which is Benjamin Graham's The Intelligent Investor. Although not a book on risk solely, it provides a different viewpoint on how to invest and covers how to protect investments via a ""Margin of Safety."" Lastly, I'd recommend Against the Gods by Peter Bernstein, which covers the history of risk and risk analysis. It's not solely a finance book but rather a fascinating historical view of risk, and it helps but many things in context. Hope it helps!" Volatility is a shitty metric and is sample dependent, What is more interesting is point recurrence, i.e. how many times has a certain point been touched in x time, you can make good day trading strategies off point recurrence (relative that is). Basically you'd take all the companies in a given universe (like the S&amp;P 500 or the Russell 3000) and instead of weighting them by market cap as they are currently done, you would weight by an alternative measure.  Right now, if you're invested in an index that is market cap weighted, you're effectively momentum chasing. If a stock runs up, you're going to have a higher weight in your portfolio because of it (but only after the increase).  An alternative that OppenheimerFunds has come up with is using revenue-weighting. That way you're using company fundamentals and only when the fundamentals are improving do you increase the weight in your portfolio.  I haven't yet seen any research that explores weighting by other fundamentals. I would think that revenues aren't perfect either and that you might want to weight by Net Income. Or to go several steps further, by year over year Free Cash Flow growth.   It could be a seminal paper if you are the one who empirically identifies a better weighting methodology and then have everyone else fight over the theoretical underpinnings.  This is effectively what goes into Smart Beta investing: http://www.investopedia.com/terms/s/smart-beta.asp The point of that question is to test if the user can connect shares and stock price.  However, that being said yeah, you're right. Probably gives off the impression that it's a bit elementary. I'll look into changing it asap. "I'll give the TLDR answer. 1) You can't forecast the price direction. If you get it right you got lucky. If you think you get it right consistently you are either a statistical anomaly or a victim of confirmation bias. Countless academic studies show that you can not do this. 2) You reduce volatility and, importantly, left-tail risk by going to an index tracking ETF or mutual fund. That is, Probability(Gigantic Loss) is MUCH lower in an index tracker. What's the trade off? The good thing is there is NO tradeoff. Your expected return does not go down in the same way the risk goes down! 3) Since point (1) is true, you are wasting time analysing companies. This has the opportunity cost of not earning $ from doing paid work, which can be thought of as a negative return. ""With all the successful investors (including myself on a not-infrequent basis) going for individual companies directly"" Actually, academic studies show that individual investors are the worst performers of all investors in the stock market." Since you seem determined to consider this, I'd like to break down for you why I believe it is an incredibly risky proposition: 1) In general, picking individual stocks is risky. Individual stocks are by their nature not diversified assets, and a single company-wide calamity (a la Volkswagen emissions, etc.) can create huge distress to your investments. The way to mitigate this risk is of course to diversify (invest in other types of assets, such as other stocks, index funds, bonds, etc.). However, you must accept that this first step does have risks.  2) Picking stocks on the basis of financial information (called 'fundamental analysis') requires a very large amount of research and time dedication. It is one of the two main schools of thought in equity investing (as opposed to 'technical analysis', which pulls information directly from stock markets, such as price volatility). This is something that professional investors do for a living - and that means that they have an edge you do not have, unless you dedicate similar resources to this task. That information imbalance between you and professional traders creates additional risk where you make determinations 'against the grain'.  3) Any specific piece of public information (and this is public information, regardless of how esoteric it is) may be considered to be already 'factored into' public stock prices. I am a believer in market efficiency first and foremost. That means I believe that anything publically known related to a corporation ['OPEC just lowered their oil production! Exxon will be able to increase their prices!'] has already been considered by the professional traders currently buying and selling in the market. For your 'new' information to be valuable, it would need to have the ability to forecast earnings in a way not already considered by others. 4) I doubt you will be able to find the true nature of the commercial impact of a particular event, simply by knowing ship locations. So what if you know Alcoa is shipping Aluminium to Cuba - is this one of 5 shipments already known to the public? Is this replacement supplies that are covering a loss due to damaged goods previously sent? Is the boat only 1/3 full? Where this information gets valuable, is when it gets to the level of corporate espionage. Yes, if you had ship manifests showing tons of aluminum being sold, and if this was a massive 'secret' shipment about to be announced at the next shareholders' meeting, you could (illegally) profit from that information. 5) The more massive the company, the less important any single transaction is. That means the super freighters you may see transporting raw commodities could have dozens of such ships out at any given time, not to mention news of new mine openings and closures, price changes, volume reports, etc. etc. So the most valuable information would be smaller companies, where a single shipment might cover a month of revenue - but such a small company is (a) less likely to be public [meaning you couldn't buy shares in the company and profit off of the information]; and (b) less likely to be found by you in the giant sea of ship information. In summary, while you may have found some information that provides insight into a company's operations, you have not shown that this information is significant and also unknown to the market. Not to mention the risks associated with picking individual stocks in the first place. In this case, it is my opinion that you are taking on additional risk not adequately compensated by additional reward. "Calculating beta is finding the correlation between the dependent variable, MSCI world benchmark, and the independent variable, your companies. If you know how to run liner regression models, run each company as the independent variable with the dependent MSCI. You can use Excel to gather this result (Y = MSCI price change at closing hour while X = company stock price closing prince). Running the regression will give you the Beta (and alpha when doing portfolios); which (from linear algebra) is the ""m"" in y = mx + b" I think by definition there aren't, generally speaking, any indicators (as in chart indicators, I assume you mean)  for fundamental analysis. Off the top of my head I can't think of one chart indicator that I wouldn't call 'technical', even though a couple could possibly go either way and I'm sure someone will help prove me wrong. But the point I want to make is that to do fundamental analysis, it is most certainly more time consuming. Depending on what instrument you're investing in, you need to have a micro perspective (company specific details) and a macro perspective (about the industry it's in). If you're investing in sector ETFs or the like, you'd be more reliant on the macro analysis. If you're investing in commodities, you'll need to consider macro analysis in multiple countries who are big producers/consumers of the item. There's no cut and dried way to do it, however I personally opt for a macro analysis of sector ETFs and then use technical analysis to determine my entry and/or exit.