Strange close in some ETFs Tuesday By: CNBC.com News March 31, 2015 at 17:38 PM EDT Strange close in a few ETFs Tuesday: Oil & Gas Exploration and Production ETF, Biotech ETF, Metals and Mining. Read More >> Related Stocks: S&P Biotech SPDR S&P Metals & Mining SPDR S&P Oil & Gas Expl & Prod SPDR