In trading on Thursday, shares of the Rare Earth/Strategic Metals ETF (REMX) entered into oversold territory, changing hands as low as $23.78 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 Rare Earth/Strategic Metals, the RSI reading has hit 26.7 — by comparison, the RSI reading for the S&P 500 is currently 53.8. A bullish investor could look at REMX's 26.7 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), REMX's low point in its 52 week range is $23.34 per share, with $37.80 as the 52 week high point — that compares with a last trade of $23.83. Rare Earth/Strategic Metals shares are currently trading off about 3% on the day.