In trading on Wednesday, shares of the iShares U.S. Telecommunications ETF ( IYZ) entered into oversold territory, changing hands as low as $29.54 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 U.S. Telecommunications, the RSI reading has hit 27.8 — by comparison, the RSI reading for the S&P 500 is currently 36.9. A bullish investor could look at IYZ'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), IYZ's low point in its 52 week range is $24.65 per share, with $34.91 as the 52 week high point — that compares with a last trade of $29.61. iShares U.S. Telecommunications shares are currently trading down about 3.6% on the day.