Point of order. Stock borrow is (more than) fully...

Point of order. Stock borrow is (more than) fully collateralised. So I can contract with you to lend you my house - this is not a rental.

You actually get the unencumbered title, but you have to give me the value of the house + "a bit more" as collateral (which I get unencumbered title). If you don't return my house to me when I ask for it, I keep your collateral.

It's up to you to decide whether it's a smart idea to sell my house after I've lent it to you because you might find it difficult to return it to me - you'd have to buy it back. Give me my house back you get your collateral back and the lending arrangement is closed.

That is how it works - it isn't a rental agreement.