I think you might be confusing two different concepts here.

Business partnerships have been around a long time, where multiple people might invest in a mill or a ferry so they could run that business and reap the profits. Business loans, where someone put up capital and it was repaid at a later date, with or without interest, existed as well.

But the concept of a corporation or publicly-traded company, where a group of people would raise capital by selling stock rather than securing a business loan, and where un-associated people could then buy that stock or otherwise invest in the company and reap the profits without directly having a say in how the company was run, didn't come about until the Middle Ages.