Ratio and Difference Symbols
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Often, it can be useful to study the ratio of two datasets to determine things like the relative strength of a stock compared to an index. StockCharts users can create ratios from two ticker symbols in our database. On our website, wherever you can enter a single ticker symbol, you can also enter two symbols joined together with a colon character (“:”), and we will use the ratio of those two symbols. We call such a combination of symbols a “Ratio Symbol.”
Here is an example of a ratio symbol in use:
People can use ratio symbols to create what is sometimes called the “Price Relative line,” the ratio of a stock against the S&P 500 Large Cap Index. For example, charting AAPL:$SPX will show you the Price Relative line for Apple Inc.
Ratio symbols are also used to create “Relative Strength” charts, which plot the ratio of two ticker symbols on a line chart. The following rules are used to interpret a relative strength chart:
The actual values for each point on the relative strength line are not relevant. Instead, focus on the direction and shape of the line.
If the line is rising, the first ticker symbol is outperforming the second ticker symbol.
If the line is falling, the second ticker symbol is outperforming the first.
On a SharpChart, the “Price” indicator can be used to add a ratio symbol to an existing chart.
Calculation: For purposes of consistency and data integrity, we use the following formulas when calculating a ratio symbol:
Open = Open of the first symbol / Close of the second symbol
High = High of the first symbol / Close of the second symbol
Low = Low of the first symbol / Close of the second symbol
Close = Close of the first symbol / Close of the second symbol
Volume = Volume of the first symbol / Volume of the second symbol
These formulas ensure that the ratio symbol's High value is still the highest and its Low value is still the lowest in the resulting dataset.
Similar to ratio symbols (see above), you can join two ticker symbols with a hyphen to create a “Difference Symbol,” e.g., $TYX-$FVX.
On a SharpChart, the “Price” indicator can be used to add a Difference Symbol to an existing chart.
Calculation:
Open = Open of the first symbol - Close of the second symbol
High = High of the first symbol - Close of the second symbol
Low = Low of the first symbol - Close of the second symbol
Close = Close of the first symbol - Close of the second symbol
