The Dutch British Empires started as companies. Nationally backed, but shareholder owned and employee run.
In any case, the lynchpin to all this trade had to be something that had value at home.. where the ships ultimately returned.
The Spanish and other empires before the Dutch & British sought gold directly. Steal it, Buy it, Mine it... Doesn't matter. This was, broadly "mercantilism." Get Gold. Bring it Home.
Adam Smith noted a century earlier that this wouldn't work. Gold has no inherent value. I think Smith was wrong on the margin, but right on the bigger point. The gold did have value. Kings could use it to raise armies, for example. The Spanish monarchy was always trying to fill its war chest. But, gold didn't fuel a trading cycle. Consumer goods & industrial materials did.
Anyway... my point is that whatever happened in between leaving London ports and returning, they were returning with goods... not gold. They may have been trading gunpowder for slaves, to be sold in the colonies and exchanged for cotton. They may have traded for spices in India. When the ships returned, they returned with goods. Tea & spices were luxury goods, that beneficiaries of the empire could enjoy. This is important, because it balanced consumption with revenue and created a cycle. Tea sippers had money because they owned shares. Revenue flowed to The Company from tea sipper. The Company used that revenue to keep bringing tea (also cotton & indigo for the mills and other luxury goods like spices). The market was secured (to an extent) by rising share values.
When a spanish ship returned with gold, someone had gold, probably the king, probably for war. When a British ship returned, someone paid gold for tea, to The Company, to fund more trade.