In trading on Thursday, shares of the First Trust Large Cap Value AlphaDEX Fund ETF ( FTA) entered into oversold territory, changing hands as low as $41.85 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 Large Cap Value AlphaDEX Fund, the RSI reading has hit 28.6 — by comparison, the RSI reading for the S&P 500 is currently 32.2. A bullish investor could look at FTA's 28.6 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), FTA's low point in its 52 week range is $35.66 per share, with $43.93 as the 52 week high point — that compares with a last trade of $41.91. First Trust Large Cap Value AlphaDEX Fund shares are currently trading off about 0.8% on the day.