On what time scales are stock support and resistance levels meaningful?
Support and resistance only works as a self-fulfilling prophecy. If everyone trading that stock agrees there's a resistance at so-and-so level, and it is on such-and-such scale, then they will trade accordingly and there will really be a support or resistance. So while you can identify them at any time scale (although as a rule the time scale on which you observed them should be similar to the time scale on which you intend to use them), it's no matter unless that's what all the other traders are thinking as well. Especially if there are multiple possible S/P levels for different time scales, there will be no consensus, and the whole system will break down as one cohort ruins the other group's S/P by not playing along and vice versa. But often fundamentals are expected to dominate in the long run, so if you are thinking of trades longer than a year, support and resistance will likely become meaningless regardless. It's not like that many people can hold the same idea for that long anyhow. "Stock support and resistance levels mean that historically, there was ""heavy"" buying/selling at those levels. This suggests, but does not guarantee, that ""someone"" will buy at ""support"" levels, and ""someone"" will sell at ""resistance levels. Any ""history"" is meaningful, but most analysts will say that after six months to a year, the impact of events declines the further back in time you go. They can be meaningful for periods as short as days."
That makes sense.  So it's sort of a thoughtless process on a short time scale, but if you add up all that noise over time you could (potentially) end up with a more meaningful position than if you had valued and bet on each stock individually.  And I could see how these things could spread along a chain to unrelated stocks as well... It’s really hard to interpret the scale of this effect.  How many listings does an area need to have for this to hold true? If a town goes from 5 listings to 25 (400% increase!) would that translate to a 15% increase in average rent? Probably not.  Percent of total housing stock being listed on Airbnb would probably be a better measurement.  At least in NYC, the city of perpetually too high rent, the rate of rent increases has been relatively low, despite the rise of Airbnb over the last few years.  Without reading the (not yet published ) study that this article is reporting on, it’s not possible to say whether the .39% increase in rent is a meaningful contribution, or a barely measurable statistic. "I can address what it means to ""pick off"" all those trades... As quantycuenta & littleadv have said, it is absolutely true that professionals ""prey"" on less-sophisticated market participants. They aren't in the market for charity's sake.  If you're not familiar with the definition of the word ""arbitrage"", look it up.  One possible strategy that can be employed with HFT machinery in order to arbitrage successfully in the stock market is to 'intercept' orders that are placed on various exchanges. In order to do this, an HFT organization watches all the transactions at once to find opportunities to buy low and sell high.  A good explanation of it is described here in this NY Times article; I'll paraphrase what that article lays out.  Stocks are traded through multiple exchanges The first key point to understand is that stocks listed on one exchange (i.e. the NYSE) can be sold on multiple exchanges. That's where the actual ""I would like to sell 100 shares of Ford stock"" is matched with ""I would like to buy 100 shares of Ford stock."" There are multiple clearinghouses on the various exchanges. Your order gets presented to one exchange at a Time An ideal market maker would like to look at the order books for a given stock, say Ford, and see that in exchange A there's a sell order for 100 shares of F at $15.85, and in exchange B there's a buy order for 100 shares of F at $15.90.  Arbitrage Market maker buys from A, sells in B, and pockets $0.05 * 100... $5. It's not much, but it was relatively risk free. Also, scale this up to the scale of the US' multiple stock exchanges, and there are lots of opportunities to make $5 every second.  Computers are (of course) faster than people To tie it in completely with your question about 'picking off trades', HFT rigs can be set up and programmed to go faster than an average retail investor's order.  Let's say you execute the trade to buy 100 shares @ $15.85 as a retail investor. The HFT rigs see your order starting to make the rounds of the different exchanges that your brokerage works through, and go out in front in a matter of milliseconds, finding the orders that are less than $15.85 and less than or equal to 100 shares. They execute a transaction, buy them up, sell to you, and pocket the difference.  You have been ""picked off"".  It's admittedly not the only way to use HFT equipment to make money, but it's definitely one way to do it." Companies do not support their stock. Once the security is out on the wild (market), its price fluctuates according to what investors think they are worth. Support is a whole different concept, financially speaking: Support or support level refers to the price level below which, historically, a stock has had difficulty falling. It is the level at which buyers tend to enter the stock. So it is the lowest assumed price for that stock. Once it reaches its price, buyers will rush to the stock, raising its price. The company wants to keep the stock price at acceptable levels, as it can be seen as the general view of the company's health. Also several employees/executives in the company have stock or stock options, so it is in their interest to keep their stock price up. A bond that goes down in value may indicate a believe the bond issuer (government in this case) won't honor the bond when it matures. As for bonds, there is a wealth of reading in this site: Can someone explain how government bonds work? Who sets the prices on government bonds?  Basic understanding of bonds, values, rates and yields "Selling as well as buying a stock are part science and part art form.  I remember once selling a stock at its 52 week high too. That particular stock ""quadrupled"" in value over the next 52 weeks.  Mind you I made 50% ROI on the stock but my point is that none of us have a crystal ball on whether a particular stock will ever stop or start going up or stop or start going down. If someone had those answers they wouldn't be telling you they would be practicing them to make more money! Make up your mind what you want to make and stick by your decisions.  Bulls make money when stocks go up and Bears make money when they go down but pigs don't make money. -RobF" "SECTION | CONTENT :--|:-- Title | ""High Profit Trades found with Candlestick Breakout Patterns"" - Stephen Bigalow Description | Originally presented on July 10, 2012.    For more information on Steve Bigalow's Candle Profit System for MetaStock visit http://www.metastock.com/products/thirdparty/?3PC-ADD-CPS  Everyone wishes they got into the fast moving stock that jumped up $25 in a month. Candlestick Signals not only identify these potential movers -- they help you identify if there is still time to participate in the move!  In this live webinar Steve will show you: Which signals produce the Breakout Patterns How to per... Length | 1:23:12           ****   ^(I am a bot, this is an auto-generated reply | )^[Info](https://www.reddit.com/u/video_descriptionbot) ^| ^[Feedback](https://www.reddit.com/message/compose/?to=video_descriptionbot&amp;subject=Feedback) ^| ^(Reply STOP to opt out permanently)" Don't have access to a Bloomberg, Eikon ect terminal but I was wondering if those that do know of any functions that show say, the percentage of companies (in different Mcap ranges) held by differing rates institutionally. For example - if I wanted to compare what percentage of small cap companies' shares are 75% or more held by institutions relative to large cap companies what could I search in the terminal? "You can infer some of the answers to your questions from the BATS exchange's market data page and its associated help page.  (I'm pretty sure a page like this exists on each stock exchange's website; BATS just happens to be the one I'm used to looking at.) The Matched Volume section refers to all trades on a given date that took place on ""lit"" exchanges; that is, where a public protected US stock exchange's matching engine helped a buyer and a seller find each other.  Because there are exactly 11 such exchanges in existence, it's easy to show 100% of the matched volume broken down into 11 rows. The FINRA & TRF Volume section refers to all trades on a given date that took place on ""non-lit"" exchanges.  These types of trades include dark pool volume and any other trade that is not required to take place in public but is required to be reported (the R in TRF) to FINRA.  There are three venues via which these trades may be reported to FINRA -- NASDAQ's, NYSE's, and FINRA's own ADF.  They're all operated under the purview of FINRA, so the fact that they're ""located at"" NASDAQ or NYSE is a red herring.  (For example, from the volume data it's clear that the NASDAQ facility does not only handle NASDAQ-listed (Tape C) securities, nor does the NYSE facility only handle NYSE-listed (Tape A) securities or anything like that.) The number of institutions reporting to each of the TRFs is large -- many more than the 11 public exchanges -- so the TRF data is not broken down further.  (Also I think the whole point of the TRFs is to report in secret.)  I don't know enough details to say why the NASDTRF has always handled more reporting volume than the other two facilities.  Of course, since we can't see inside the TRF reporting anyway, it's sort of a moot point."