In trading on Thursday, shares of the iShares MSCI South Africa ETF ( EZA) entered into oversold territory, changing hands as low as $61.49 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 MSCI South Africa, the RSI reading has hit 28.8 — by comparison, the RSI reading for the S&P 500 is currently 52.6. A bullish investor could look at EZA's 28.8 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), EZA's low point in its 52 week range is $55.31 per share, with $72.77 as the 52 week high point — that compares with a last trade of $61.59. iShares MSCI South Africa shares are currently trading off about 1.9% on the day.