A look at the weighted underlying holdings of the Vanguard Energy ETF (VDE) shows an impressive 16.3% 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 » Occidental Petroleum Corp (OXY), which makes up 4.22% of the Vanguard Energy ETF (VDE), has seen 10 directors and officers purchase shares in the past six months, according to the recent Form 4 data.