In 1850 Swenson moved to Austin, Texas and established a mercantile business with his uncle Swante Palm.
While running the business, Swenson continued to buy railroad land and then bought school scripts to acquire additional property.
In 1854 Svenson invested in the Buffalo Bayou, Brazos and Colorado Railway, which gained him acres of land in northwestern and western Texas.
At their peak, the SMS Ranches occupy considerable portions of twelve counties in the lower plains area of West Texas and comprise more than 300,000 acres (1,200 km2).
The SMS brand, consisting of an extended M sandwiched between two reversed S's, was registered by the Swensons in the spring of 1882.