In trading on Monday, shares of the Guggenheim S&P 500 Equal Weight Energy ETF ( RYE) entered into oversold territory, changing hands as low as $65.508 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 Guggenheim S&P 500 Equal Weight Energy, the RSI reading has hit 28.4 — by comparison, the RSI reading for the S&P 500 is currently 66.1. A bullish investor could look at RYE's 28.4 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), RYE's low point in its 52 week range is $65.508 per share, with $95.24 as the 52 week high point — that compares with a last trade of $65.75. Guggenheim S&P 500 Equal Weight Energy shares are currently trading off about 4.6% on the day.