In trading on Monday, shares of the ETFS Physical Silver Shares ETF ( SIVR) entered into oversold territory, changing hands as low as $18.7438 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 ETFS Physical Silver Shares, the RSI reading has hit 27.8 — by comparison, the RSI reading for the S&P 500 is currently 58.6. A bullish investor could look at SIVR's 27.8 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), SIVR's low point in its 52 week range is $18.39 per share, with $23.64 as the 52 week high point — that compares with a last trade of $18.76. ETFS Physical Silver Shares shares are currently trading off about 0.8% on the day.