In trading on Wednesday, shares of the iShares North American Natural Resources ETF ( IGE) entered into oversold territory, changing hands as low as $45.0101 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 iShares North American Natural Resources, the RSI reading has hit 26.0 — by comparison, the RSI reading for the S&P 500 is currently 51.5. A bullish investor could look at IGE's 26.0 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), IGE's low point in its 52 week range is $40.53 per share, with $50.50 as the 52 week high point — that compares with a last trade of $45.19. iShares North American Natural Resources shares are currently trading off about 1.1% on the day.