In trading on Monday, shares of the Guggenheim China Real Estate ETF ( TAO) entered into oversold territory, changing hands as low as $20.3682 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 Guggenheim China Real Estate, the RSI reading has hit 27.2 — by comparison, the RSI reading for the S&P 500 is currently 47.2. A bullish investor could look at TAO's 27.2 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), TAO's low point in its 52 week range is $17.86 per share, with $22.95 as the 52 week high point — that compares with a last trade of $20.52. Guggenheim China Real Estate shares are currently trading down about 3.8% on the day.