When you deposit money into a bank account, it doesn’t just sit in a vault waiting for you to use it. In fact, while you’re asleep, your bank is often busy moving your money in ways you may not realize. The modern banking system doesn’t require banks to keep all your cash on hand. Instead, they’re permitted, and even encouraged, to use your money to make more money.
Through a process known as fractional reserve banking, financial institutions only have to keep a small percentage of deposits available in reserve. The rest can be loaned out, invested, or shuffled between accounts. These decisions are typically automated, handled overnight by high-frequency trading systems, lending algorithms, or interbank transfers. It’s all legal—and it’s all happening while you sleep.
