In trading on Friday, shares of the iShares Morningstar Small-Cap ETF ( JKJ) entered into oversold territory, changing hands as low as $129.31 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 Morningstar Small-Cap, the RSI reading has hit 29.7 — by comparison, the RSI reading for the S&P 500 is currently 33.6. A bullish investor could look at JKJ's 29.7 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), JKJ's low point in its 52 week range is $111.99 per share, with $139.61 as the 52 week high point — that compares with a last trade of $129.66. iShares Morningstar Small-Cap shares are currently trading down about 0.8% on the day.