If you're buying newly issued stock, that's going to be directly spent on business expenses like salaries and payments to other companies. Even buying existing

If you're buying newly issued stock, that's going to be directly spent on business expenses like salaries and payments to other companies. Even buying existing stock directly supports the market for companies to raise money in that way. If you're buying existing stock, someone on the other end is receiving your money that they will then spend or invest as they see fit. Very little money is idle, since it's in no one's interests for it to be.