Texas Pacific Land Corporation owns roughly the area of a small state in west Texas, land granted to a railroad in the 1880s and now sitting atop the Permian Basin, America's most productive oil field. The company does not drill. It collects royalties when others produce oil and gas on its acreage, sells water and easements to operators, and incurs almost no cost doing so. Margins are consequently extraordinary. With the land owned outright and forever, TPL functions as a perpetual, debt-free claim on Permian activity.