Complex sentence: Since 1985, the Market had been managed by the Shantz family, but in late November 2017, the Market was sold by the Mercedes Corp., with its 40 shareholders including the Shantz families.
Split into simpler sentences: Since 1985, the Market had been managed by the Shantz family, but in late November 2017, the Market was sold. By that time, the owner was the Mercedes Corp., with 40 shareholders including the Shantz families.