In trading on Tuesday, shares of the Health Care GEMS ETF ( HGEM) entered into oversold territory, changing hands as low as $22.92 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 Health Care GEMS, the RSI reading has hit 26.6 — by comparison, the RSI reading for the S&P 500 is currently 51.2. A bullish investor could look at HGEM's 26.6 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), HGEM's low point in its 52 week range is $18.47 per share, with $25.30 as the 52 week high point — that compares with a last trade of $23.00. Health Care GEMS shares are currently trading off about 2.2% on the day.