In trading on Thursday, shares of the First Trust Large Cap Growth AlphaDEX Fund ETF ( FTC) entered into oversold territory, changing hands as low as $47.33 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 Growth AlphaDEX Fund, the RSI reading has hit 29.5 — by comparison, the RSI reading for the S&P 500 is currently 33.4. A bullish investor could look at FTC's 29.5 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), FTC's low point in its 52 week range is $42.01 per share, with $51.67 as the 52 week high point — that compares with a last trade of $47.35. First Trust Large Cap Growth AlphaDEX Fund shares are currently trading off about 0.3% on the day.