The Public Short Ratio ("PSR") shows the
relationship between the number of public short sales and the total
number of short sales. (The Public Short Ratio is sometimes referred to
as the non-member short ratio.)
Interpretation
The interpretation of the PSR assumes one premise:
that of the short sellers, the public is the worst (well, except for the
odd lot traders whose indicators begin with the Odd Lot Balance Index).
If this is true, then we should buy when the public is shorting and sell
when the public is long. Historically, this premise has held true.
Generally speaking, the higher the PSR, the more
bearish the public, and the more likely prices will increase (given the
above premise). Historically, it has been considered bullish when the
10-week moving average of the PSR is above 25% and bearish when the
moving average is below 25%. The further the moving average is in the
bullish or bearish territory, the more likely it is that a correction/
rally will take place. Also, the longer the indicator is in the
bullish/bearish territory, the better the chances of a market move. For
more information on the PSR, I suggest reading the discussion on the
non-member short ratio in Stock Market Logic, by Norman G. Fosback.
Example
The following chart shows the New York Stock
Exchange Index and a 10-week moving average of the Public Short Ratio.
The PSR dropped below 25% into bearish territory at
the point labeled "A." Over the next several months, the PSR continued
to move lower as the public became more and more bullish. During this
period, prices surged upward adding to the bullish frenzy. The
subsequent crash of 1987 gave the public a strong dose of reality.
Since the crash of 1987, the PSR has remained high,
telling us that the public doesn't expect higher prices--a bullish sign.
Calculation
The Public Short Ratio is calculated by dividing the
number of public short sales by the total number of short sales. The
result is the percent-age of public shorts.