It's not really about presentation of balance sheets, it's about liquidity. The explicit purpose of market makers is to provide liquidity, so they have a specia

It's not really about presentation of balance sheets, it's about liquidity. The explicit purpose of market makers is to provide liquidity, so they have a special exemption to buy and sell shares without being certain they exist. They have to have a good faith belief they will exist though. Usually they're right. Occasionally they're wrong.