Concho Resources (NYSE: CXO) has quietly flown under the radar of investors over the past year. Its stock has basically flatlined while popular shale drillers EOG Resources (NYSE: EOG) and Encana (NYSE: ECA) are up more than 7% even as crude has slumped 13%. One result of that underperformance is that Concho’s stock trades for just 12 times enterprise value-to-EBITDA, while its rivals fetch 19 times EV-to-EBITDA multiples.