3. Apart from minor fluctuations the prices of individual securities, and the level of the market as a whole, tend to move in trends which persist for significant periods of time.
4. Trends change in reaction to shifts in supply and demand. These shifts in supply and demand can be detected in the action of the market itself.
Assumptions 3 and 4 are controversial.
Supporters of the efficient market hypothesis (EMH) take the view that new information is very quickly reflected in security prices. If information is very quickly reflected in prices, trends do not have an opportunity to emerge. Technical analysts believe that new
information does not arrive in the market at a single point in time; they take the view that new information comes to the market over a period of time. For example new information may be available first to insiders, second to professionals, and lastly to the public.
As the information gradually becomes more widely available, the share price gradually moves to its new equilibrium price. Technical analysts look for the beginning of a movement from one equilibrium price to another without attempting to predict the new equilibrium price.
They attempt to profit from forecasting the direction of movement; that is they try to identify trends and profit from them.
Whatever the reason for a change in price, if the share price responds sufficiently slowly, a trend emerges. A slow response of prices to shifts in supply and demand provides the potential to profit from technical analysis.
There are many technical analysis and trading techniques, including chart and non-chart ones.
Price charts are a more frequent technique. Price charts are made for each day, or other chosen time interval, with the help of a vertical line. The top of the vertical line indicates the highest price reached during the day and the bottom shows the lowest price. A short horizontal line on each vertical line indicates the closing price on the day.
A variety of price charts include line charts, Japanese candlestick charts, a point-and figure.
One aim of the charts is to find areas where price reversals are frequent since this is seen as presaging a substantial price movement (break out from a trading range).This would appear as a horizontal stretching out of the chart.
Technical analysts use a vast number of chart patterns.
Price channels (Trend channels). Trend channels can be horizontal, upward or downward sloping. The share price remains within the channel, and some points in time breaks out of the channel. If it breaks out o f the channel in a downward direction, the chartist may interpret this as a signal to sell the stock since it is seen as forecasting a fall in the stock price, and vise versa. Price channels are often interpreted in terms of the bounds providing limits to the extent of variation of share prices, such that share prices tend to remain within
the bounds.
Reversal patterns. Chartists frequently believe that when the direction of a share price (or market index) changes, characteristic chart patterns may develop as the turn occurs. One of those reversal patterns is head-and-shoulders configuration. The highest peak is the head, and the lower peaks are the shoulders. When the share price falls below the lower peak, further price fall is forecasted and eventually constitutes a sell signal.
Converse reasoning would explain the use of reverse head-and-shoulders, which indicates that stock prices will rise and that therefore shares should be bought.