Oppenheimer Reduces Stake in Invesco S&P MidCap 400 Pure Growth ETF Oppenheimer & Co. Inc. has decreased its holdings in the Invesco S&P MidCap 400 Pure Growth ETF by 3.9%, selling 305 shares during the fourth quarter. The fund now holds 7,546 shares, valued at $365,000. This adjustment comes amidst fluctuating performance metrics for the ETF, which targets growth-focused mid-cap stocks.12