In trading on Friday, shares of the SPDR Nuveen Barclays Build America Bond ETF ( BABS) entered into oversold territory, changing hands as low as $54.27 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 SPDR Nuveen Barclays Build America Bond, the RSI reading has hit 29.6 — by comparison, the RSI reading for the S&P 500 is currently 46.9. A bullish investor could look at BABS's 29.6 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), BABS's low point in its 52 week range is $53.47 per share, with $65.63 as the 52 week high point — that compares with a last trade of $54.45. SPDR Nuveen Barclays Build America Bond shares are currently trading off about 1.1% on the day.