In trading on Monday, shares of the Rare Earth/Strategic Metals ETF ( REMX) entered into oversold territory, changing hands as low as $10.11 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 26.9 — by comparison, the RSI reading for the S&P 500 is currently 52.0. A bullish investor could look at REMX's 26.9 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 $10.11 per share, with $16.89 as the 52 week high point — that compares with a last trade of $10.12. Rare Earth/Strategic Metals shares are currently trading off about 6.8% on the day.