In trading on Tuesday, shares of the Vanguard Short-Term Inflation-Protected Securities ETF ( VTIP) entered into oversold territory, changing hands as low as $49.67 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 Vanguard Short-Term Inflation-Protected Securities, the RSI reading has hit 29.3 — by comparison, the RSI reading for the S&P 500 is currently 52.2. A bullish investor could look at VTIP'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), VTIP's low point in its 52 week range is $48.90 per share, with $52.13 as the 52 week high point — that compares with a last trade of $49.68. Vanguard Short-Term Inflation-Protected Securities shares are currently trading down about 0.1% on the day.