In trading on Wednesday, shares of the First Trust Developed Markets Ex-US AlphaDEX Fund ETF ( FDT) entered into oversold territory, changing hands as low as $50.698 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 First Trust Developed Markets Ex-US AlphaDEX Fund, the RSI reading has hit 29.4 — by comparison, the RSI reading for the S&P 500 is currently 35.8. A bullish investor could look at FDT's 29.4 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), FDT's low point in its 52 week range is $45.92 per share, with $54.15 as the 52 week high point — that compares with a last trade of $50.76. First Trust Developed Markets Ex-US AlphaDEX Fund shares are currently trading down about 0.7% on the day.