In trading on Wednesday, shares of the iShares Silver Trust ETF ( SLV) entered into oversold territory, changing hands as low as $21.73 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 Silver Trust, the RSI reading has hit 28.5 — by comparison, the RSI reading for the S&P 500 is currently 70.6. A bullish investor could look at SLV's 28.5 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), SLV's low point in its 52 week range is $21.73 per share, with $34.08 as the 52 week high point — that compares with a last trade of $21.89. iShares Silver Trust shares are currently trading down about 3.2% on the day.