In trading on Friday, shares of the ETFS Physical Swiss Gold Shares ETF ( SGOL) entered into oversold territory, changing hands as low as $146.33 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 Swiss Gold Shares, the RSI reading has hit 24.6 — by comparison, the RSI reading for the S&P 500 is currently 68.3. A bullish investor could look at SGOL's 24.6 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), SGOL's low point in its 52 week range is $146.33 per share, with $177.44 as the 52 week high point — that compares with a last trade of $146.79. ETFS Physical Swiss Gold Shares shares are currently trading down about 4.7% on the day.