In trading on Tuesday, shares of the iShares Global Infrastructure ETF (IGF) entered into oversold territory, changing hands as low as $42.1864 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 Global Infrastructure, the RSI reading has hit 28.1 — by comparison, the RSI reading for the S&P 500 is currently 34.9. A bullish investor could look at IGF's 28.1 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), IGF's low point in its 52 week range is $35.33 per share, with $44.68 as the 52 week high point — that compares with a last trade of $42.28. iShares Global Infrastructure shares are currently trading down about 1.6% on the day.