In trading on Friday, shares of the Proshares UltraPro Short Russell2000 ETF (SRTY) entered into oversold territory, changing hands as low as $19.27 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 UltraPro Short Russell2000, the RSI reading has hit 29.8 — by comparison, the RSI reading for the S&P 500 is currently 72.9. A bullish investor could look at SRTY's 29.8 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), SRTY's low point in its 52 week range is $19.27 per share, with $61.43 as the 52 week high point — that compares with a last trade of $19.29. Proshares UltraPro Short Russell2000 shares are currently trading off about 3.4% on the day.