Was the joint stock company principal instrument of overseas expansion?

The joint-stock company was not the principal instrument of overseas expansion for European powers in the 15th and 16th centuries contrary to the provided answer. While the joint-stock company was an important innovation that facilitated overseas trade and colonization, other factors such as advancements in maritime technology, the search for new trade routes, and the accumulation of wealth through trade and economic growth played a more significant role in driving European overseas expansion.