Periodicity in stock charts
If the period is consistent for company X, but occurs in a different month as Company Y, it might be linked to the release of their annual report, or the payment of their annual dividend. Companies don't have to end their fiscal year near the end of the Calendar year, therefore these end of year events could occur in any month. The annual report could cause investors to react to the hard numbers of the report compared to what wall street experts have been predicting. The payment of an annual dividend will also cause a direct drop in the price of the stock when the payment is made. There will also be some movement in prices as the payment date approaches.
"Google's RSI is using a 10 period on 2 minute bars - i.e. it is based upon the last 20 minutes of data. Yahoo's RSI is using a 14 period lookback on an undetermined timeframe (you could maybe mouse-over and see what incremental part of the chart is giving) and given the ""choppier"" price chart, probably 30 second or 1 minute bars.   Given the difference in both the period specified and the periodicity of the charts - you should expect different results." That is called a 'volume chart'. There are many interactive charts available for the purpose. Here is clear example.  (just for demonstration but this is for India only) 1) Yahoo Finance 2) Google Finance 3) And many more Usually, the stock volume density is presented together (below it) with normal price vs time chart. Note: There is a friendly site about topics like this. Quant.stackexchange.com. Think of checking it out. "I would have to disagree with the other responders. In technical analysis of stock charts, various short and long term moving averages are used to give an indication of the trend of the stock in the short and long term, as compared to the current price. I would prefer to use the term moving average (MA) rather than average as the MA is recalculated every day (or at appropriate frequencies for your data) on the period you are using. I would also expand on the term ""moving average"". There are two that are commonly used Going back to the question, of the value of this number, For example if the current price is above the 200 day EWMA and also above the 30 day EWMA, then the stock is broadly trending upwards. Conversely if current price is below the 200 day EWMA and also below the 30 day EWMA, then the stock is broadly trending downwards. These numbers are chosen on the basis of the market you are trading in, the volatility and other factors. For another example of how a number of moving averages are used together, please have a read of Daryl Guppy's Multiple Moving Average, though this does not use moving averages as large as 200 days." Moving Average is mere average line based on historical period; broadly use to view the trend. But it has no relation to price action in due future course. If price is going below 20 SMA then in near future even the SMA will start directing toward south. In your case if price has fallen below all the short period average lines and long period average line then it is bearish in nature. Soon in few days you may find 20 SMA leading downwards followed by closest period and then long. Also SMA and EMA can best be observed in charting software in candlestick mode. Because these moving averages can also be adjusted and viewed based on Opening price, High prices, Low Price or closing price. In you case I guess the data is of closing price data. Overlapping of averages may be sign of reversals. So if you want to buy this stock you may have to wait till all the average lines cross-over and when new trend begins with SMA of shortest avg period (20) leading above the long avg period (90 days in your case). Then you can buy and just follow the trend. I hope it answers you question. Candlesticks and TA are a relic of pre-computer trading, period. Market makers use sophisticated algorithms not for trading, but manipulations. Here in Australia a stock price is usually highest just before a dividend and lowest just after a dividend. If you buy just after the dividend then you missed out until next time. There may be many other reasons why a stock may exhibit yearly, quarterly and monthly cycles. "This chart concerns an option contract, not a stock. The method of analysis is to assume that the price of an option contract is normally distributed around some mean which is presumably the current price of the underlying asset. As the date of expiration of the contract gets closer the variation around the mean in the possible end price for the contract will decrease. Undoubtedly the publisher has measured typical deviations from the mean as a function of time until expiration from historical data. Based on this data, the program that computes the probability has the following inputs: (1) the mean (current asset price) (2) the time until expiration (3) the expected standard deviation based on (2) With this information the probability distribution that you see is generated (the green hump). This is a ""normal"" or Gaussian distribution. For a normal distribution the probability of a particular event is equal to the area under the curve to the right of the value line (in the example above the value chosen is 122.49). This area can be computed with the formula:  This formula is called the probability density for x, where x is the value (122.49 in the example above). Tau (T) is the reciprocal of the variance (which can be computed from the standard deviation). Mu (μ) is the mean. The main assumption such a calculation makes is that the price of the asset will not change between now and the time of expiration. Obviously that is not true in most cases because the prices of stocks and bonds constantly fluctuate. A secondary assumption is that the distribution of the option price around the mean will a normal (or Gaussian) distribution. This is obviously a crude assumption and common sense would suggest it is not the most accurate distribution. In fact, various studies have shown that the Burr Distribution is actually a more accurate model for the distribution of option contract prices." "The Securities Industry and Financial Markets Association (SIFMA) publishes these and other relevant data on their Statistics page, in the ""Treasury & Agency"" section. The volume spreadsheet contains annual and monthly data with bins for varying maturities. These data only go back as far as January 2001 (in most cases). SIFMA also publishes treasury issuances with monthly data for bills, notes, bonds, etc. going back as far as January 1980. Most of this information comes from the Daily Treasury Statements, so that's another source of specific information that you could aggregate yourself. Somewhere I have a parser for the historical data (since the Treasury doesn't provide it directly; it's only available as daily text files). I'll post it if I can find it. It's buried somewhere at home, I think."