In trading on Friday, shares of the SPDR Nuveen Barclays California Municipal Bond ETF ( CXA) entered into oversold territory, changing hands as low as $23.67 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 California Municipal Bond, the RSI reading has hit 29.8 — by comparison, the RSI reading for the S&P 500 is currently 53.4. A bullish investor could look at CXA's 29.8 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), CXA's low point in its 52 week range is $23.11 per share, with $24.62 as the 52 week high point — that compares with a last trade of $23.69. SPDR Nuveen Barclays California Municipal Bond shares are currently trading down about 0.4% on the day.