In trading on Tuesday, shares of the PowerShares KBW Premium Yield Equity REIT Portfolio ETF (KBWY) entered into oversold territory, changing hands as low as $31.80 per share. We define oversold territory using the Relative Strength Index, or RSI, which is a technical analysis indicator used to measure momentum on a scale of zero to 100. A stock is considered to be oversold if the RSI reading falls below 30.In the case of PowerShares KBW Premium Yield Equity REIT Portfolio, the RSI reading has hit 28.9 — by comparison, the RSI reading for the S&P 500 is currently 36.9. A bullish investor could look at KBWY's 28.9 reading as a sign that the recent heavy selling is in the process of exhausting itself, and begin to look for entry point opportunities on the buy side. Looking at a chart of one year performance (below), KBWY's low point in its 52 week range is $30.63 per share, with $38.18 as the 52 week high point — that compares with a last trade of $31.80. PowerShares KBW Premium Yield Equity REIT Portfolio shares are currently trading down about 0.8% on the day.