XOM +0.8% +12.8% CVX +2.9% +10% COP +2.1% +50% OXY +7.2% +33.1% SLB -0.3% +33.4% RIG -2.7% +30.6% VLO +3% +16.8% MPC +1.1% +26.5% The Energy Select Sector SPDR — a popular way to track energy companies — was up 1.1% last week. The best performer was Houston-TX based biggie Occidental Petroleum ( OXY - Free Report ) whose stock climbed 7.2%. Over the past six months, the sector tracker has increased 20.8%. Upstream biggie ConocoPhillips ( COP - Free Report ) was the major gainer during the period, experiencing a 50% price appreciation.