Complex sentence: The storehouse continued to operate until 1848, the year in which the Russian American Company assumed ownership, and subsequently managed until as far as 1867, the year in which the Russian American Company went out of business.
Split into simpler sentences: The storehouse continued to operate until 1848, the year in which the Russian American Company assumed ownership. It managed the store until as far as 1867, the year in which the Russian American Company went out of business.