What You Don’t Know About Relative Strength Shifts In ETFs Can Hurt You

One of the best web sites for identifying trends in the ETF marketplace is ETFscreen.com. And one of the best features at the data aggregation portal is the Relative Strength Factor (RSf) reporting.

According to ETF Screen, the Relative Strength Factor (RSf) represents a percentile ranking of fund performance relative to all other funds in the universe. While it is measured over an entire year, the factor heavily weights recent performance to identify funds that have been accelerating versus those that have been deteriorating. The higher the percentile rank (0-99.99), the greater the relative strength.

One method to visualize meaningful changes over time is to see the data on a quarter-over-quarter basis. For example, iShares Biotechnology (IBB) registered a RSf rank of 98.9 at the beginning of February. At the start of May, though, the seemingly unstoppable biotech bellwether slipped to a modest 67.1. Conversely, Market Vectors Small Cap India (SCIF) had been woefully unappreciated back on 2/4/14 when it logged in at 23.4. Three months later, SCIF resides in the top decile (98.3) of the exchange-traded fund universe.

These individual stories may meet a criterion for “nice-to-know info.” However, when it comes to chin-rubbing fascination, one usually needs to see shifts in major asset classes.