In trading on Friday, shares of the Emerging Markets Infrastructure Portfolio ETF (PXR) PXR entered into oversold territory, changing hands as low as $39.71 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 Emerging Markets Infrastructure Portfolio, the RSI reading has hit 29.3 — by comparison, the RSI reading for the S&P 500 is currently 47.8. A bullish investor could look at PXR's 29.3 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), PXR's low point in its 52 week range is $35.60 per share, with $44.78 as the 52 week high point — that compares with a last trade of $39.89. Emerging Markets Infrastructure Portfolio shares are currently trading down about 1.1% on the day.