Did Studebaker own STP?

Could you elaborate on the relationship between Studebaker and STP? I've heard some speculation that Studebaker may have had ownership of STP, but I'm not entirely sure. Is there any concrete evidence to support this claim? Did Studebaker acquire STP through a merger, acquisition, or some other means? Or was STP a separate entity that Studebaker simply had some affiliation with? Clarifying this relationship would help me better understand the historical context and significance of both Studebaker and STP.