In trading on Monday, shares of the ProShares UltraShort Real Estate ETF ( SRS) entered into oversold territory, changing hands as low as $13.31 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 ProShares UltraShort Real Estate, the RSI reading has hit 28.7 — by comparison, the RSI reading for the S&P 500 is currently 79.4. A bullish investor could look at SRS's 28.7 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), SRS's low point in its 52 week range is $13.31 per share, with $22.89 as the 52 week high point — that compares with a last trade of $13.38. ProShares UltraShort Real Estate shares are currently trading off about 0.7% on the day.