In trading on Tuesday, shares of the Proshares UltraPro Short MidCap400 ETF ( SMDD) entered into oversold territory, changing hands as low as $39.83 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 Proshares UltraPro Short MidCap400, the RSI reading has hit 28.6 — by comparison, the RSI reading for the S&P 500 is currently 67.8. A bullish investor could look at SMDD's 28.6 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), SMDD's low point in its 52 week range is $39.83 per share, with $86.76 as the 52 week high point — that compares with a last trade of $39.87. Proshares UltraPro Short MidCap400 shares are currently trading off about 1.9% on the day.