In trading on Thursday, shares of the iShares MSCI Global Energy Producers ETF ( FILL) entered into oversold territory, changing hands as low as $21.006 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 Global Energy Producers, the RSI reading has hit 29.9 — by comparison, the RSI reading for the S&P 500 is currently 44.7. A bullish investor could look at FILL's 29.9 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), FILL's low point in its 52 week range is $19.76 per share, with $30.01 as the 52 week high point — that compares with a last trade of $21.05. iShares MSCI Global Energy Producers shares are currently trading off about 1.5% on the day.