In trading on Friday, shares of the Euro Trust ETF ( FXE) entered into oversold territory, changing hands as low as $126.58 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 Euro Trust, the RSI reading has hit 27.4 — by comparison, the RSI reading for the S&P 500 is currently 67.5. A bullish investor could look at FXE's 27.4 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), FXE's low point in its 52 week range is $126.54 per share, with $137.87 as the 52 week high point — that compares with a last trade of $126.59. Euro Trust shares are currently trading off about 0.6% on the day.