In trading on Friday, shares of the ProShares Ultra FTSE Europe ETF ( UPV) entered into oversold territory, changing hands as low as $42.56 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 FTSE Europe, the RSI reading has hit 28.5 — by comparison, the RSI reading for the S&P 500 is currently 43.1. A bullish investor could look at UPV's 28.5 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), UPV's low point in its 52 week range is $38.73 per share, with $57.90 as the 52 week high point — that compares with a last trade of $42.56. ProShares Ultra FTSE Europe shares are currently trading off about 4.1% on the day.