In trading on Monday, shares of the ProShares Ultra 20+ Year Treasury ETF (UBT) entered into oversold territory, changing hands as low as $76.63 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 Ultra 20+ Year Treasury, the RSI reading has hit 28.2 — by comparison, the RSI reading for the S&P 500 is currently 55.2. A bullish investor could look at UBT's 28.2 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), UBT's low point in its 52 week range is $60.86 per share, with $97.00 as the 52 week high point — that compares with a last trade of $76.83. ProShares Ultra 20+ Year Treasury shares are currently trading down about 2% on the day.