In trading on Tuesday, shares of the PowerShares Dynamic Building & Construction Portfolio ETF ( PKB) entered into oversold territory, changing hands as low as $20.88 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 Dynamic Building & Construction Portfolio, the RSI reading has hit 29.9 — by comparison, the RSI reading for the S&P 500 is currently 48.5. A bullish investor could look at PKB's 29.9 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), PKB's low point in its 52 week range is $19.52 per share, with $23.68 as the 52 week high point — that compares with a last trade of $20.90. PowerShares Dynamic Building & Construction Portfolio shares are currently trading down about 0.7% on the day.