A look at the weighted underlying holdings of the SPDR S&P MIDCAP 400 ETF Trust (MDY) shows an impressive 10.2% of holdings on a weighted basis have experienced insider buying within the past six months. Start slideshow:10 ETFs With Stocks That Insiders Are Buying » Middleby Corp (MIDD), which makes up 0.38% of the SPDR S&P MIDCAP 400 ETF Trust (MDY), has seen 2 directors and officers purchase shares in the past six months, according to the recent Form 4 data.