In trading on Tuesday, shares of the Proshares UltraPro Dow30 ETF ( UDOW) entered into oversold territory, changing hands as low as $109.12 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 Dow30, the RSI reading has hit 28.8 — by comparison, the RSI reading for the S&P 500 is currently 34.9. A bullish investor could look at UDOW's 28.8 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), UDOW's low point in its 52 week range is $78.90 per share, with $125.88 as the 52 week high point — that compares with a last trade of $110.00. Proshares UltraPro Dow30 shares are currently trading off about 2.9% on the day.