Technical analysis is based almost entirely on the
analysis of price and volume. The fields which define a security's price
and volume are explained below.
Open - This is the price of the first trade
for the period (e.g., the first trade of the day). When analyzing daily
data, the Open is especially important as it is the consensus price
after all interested parties were able to "sleep on it."
High - This is the highest price that the
security traded during the period. It is the point at which there were
more sellers than buyers (i.e., there are always sellers willing to sell
at higher prices, but the High represents the highest price buyers were
willing to pay).
Low - This is the lowest price that the
security traded during the period. It is the point at which there were
more buyers than sellers (i.e., there are always buyers willing to buy
at lower prices, but the Low represents the lowest price sellers were
willing to accept).
Close - This is the last price that the
security traded during the period. Due to its availability, the Close is
the most often used price for analysis. The relationship between the
Open (the first price) and the Close (the last price) are considered
significant by most technicians. This relationship is emphasized in
candlestick charts.
Volume - This is the number of shares (or
contracts) that were traded during the period. The relationship between
prices and volume (e.g., increasing prices accompanied with increasing
volume) is important.
Open Interest - This is the total number of
outstanding contracts (i.e., those that have not been exercised, closed,
or expired) of a future or option. Open interest is often used as an
indicator.
Bid - This is the price a market maker is
willing to pay for a security (i.e., the price you will receive if you
sell).
Ask - This is the price a market maker is
willing to accept (i.e., the price you will pay to buy the security).
These simple fields are used to create literally
hundreds of technical tools that study price relationships, trends,
patterns, etc.
Not all of these price fields are available for all
security types, and many quote providers publish only a subset of these.
Table 1 shows the typical fields that are reported for several security
types.