In trading on Monday, shares of C&J Energy Services Inc. ( CJES) entered into oversold territory, changing hands as low as $13.461 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 C&J Energy Services Inc., the RSI reading has hit 28.1 — by comparison, the universe of energy stocks covered by Energy Stock Channel currently has an average RSI of 40.6, the RSI of WTI Crude Oil is at 28.0, and the RSI of Henry Hub Natural Gas is presently 45.7. A bullish investor could look at CJES'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), CJES's low point in its 52 week range is $13.46 per share, with $34.93 as the 52 week high point — that compares with a last trade of $13.47. C&J Energy Services Inc. shares are currently trading down about 10.5% on the day. According to the ETF Finder at ETF Channel, CJES makes up 1.49% of the SPDR S&P Oil & Gas Equipment & Services ETF ( XES) which is trading lower by about 3.9% on the day Monday.