Shares of Vanguard S&P Mid-Cap 400 ETF (NYSEARCA:IVOO – Get Free Report) saw unusually-high trading volume on Wednesday . Approximately 130,913 shares traded hands during mid-day trading, an increase of 141% from the previous session’s volume of 54,328 shares.The stock last traded at $100.71 and had previously closed at $98.79. Vanguard S&P Mid-Cap 400 ETF […]