In trading on Wednesday, shares of the Proshares Ultra DJ-UBS Crude Oil ETF ( UCO) entered into oversold territory, changing hands as low as $31.01 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 DJ-UBS Crude Oil, the RSI reading has hit 29.2 — by comparison, the RSI reading for the S&P 500 is currently 64.8. A bullish investor could look at UCO's 29.2 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), UCO's low point in its 52 week range is $24.75 per share, with $40.02 as the 52 week high point — that compares with a last trade of $31.20. Proshares Ultra DJ-UBS Crude Oil shares are currently trading off about 3.6% on the day.