In trading on Tuesday, shares of the PowerShares Golden Dragon China Portfolio ETF ( PGJ) entered into oversold territory, changing hands as low as $27.521 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 Golden Dragon China Portfolio, the RSI reading has hit 26.7 — by comparison, the RSI reading for the S&P 500 is currently 51.5. A bullish investor could look at PGJ's 26.7 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), PGJ's low point in its 52 week range is $26.45 per share, with $34.62 as the 52 week high point — that compares with a last trade of $27.73. PowerShares Golden Dragon China Portfolio shares are currently trading off about 2% on the day.