In trading on Friday, shares of the BLDRS Emerging Markets 50 ADR Index Fund ETF (ADRE) ADRE entered into oversold territory, changing hands as low as $37.09 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 BLDRS Emerging Markets 50 ADR Index Fund, the RSI reading has hit 28.5 — by comparison, the RSI reading for the S&P 500 is currently 47.8. A bullish investor could look at ADRE'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), ADRE's low point in its 52 week range is $35.27 per share, with $41.85 as the 52 week high point — that compares with a last trade of $37.33. BLDRS Emerging Markets 50 ADR Index Fund shares are currently trading down about 1.2% on the day.