For anyone who can be bothered, here is the full version that extract was take from.
The Bank of England published a paper in 2014 supporting the credit creation theory of money. The theory has been around for a long time, but for most of the last 100 years other theories have been favoured. The paper has triggered lots of web chatter about the nature of money, including this post.
97% of money in circulation is of the type "bank deposits". Deposits are created "out of thin air" when a commercial bank makes a loan to a customer.
Imagine the bank loans 10K to a customer. To effect this, it debits a loan account by 10K and credits a bank account with 10K. A loan account balance is a debt the customer owes the bank, and a bank account balance is a debt the bank owes a customer. The 10K credited to a bank account is a called a deposit.
Deposits are transferable. When the customer uses the loan to buy a car, the deposit moves to the bank account of the car seller, possibly at a different bank. The fact that deposits are transferable makes them a kind of money. 97% of the money in circulation in the UK is transferable debt created by commercial banks.
When there is a loan repayment, a bank account is debited and a loan account is credited by the same amount, that amount of money has been destroyed.
Although neither the bank nor the customer became any better or worse off when the loan was made, because of the two offsetting debts, 10K of money was created "out of thin air", because only one of the two debts is freely transferable, and is therefore money.
While its ability to create money means a bank does not have to first have 10K in order to lend it, if the 10K deposit it creates moves to another bank, the bank has to find 10K from somewhere to fund the transfer. In reality, with lots of transactions causing funds to flow in both directions, it's only the net flow of funds to the other bank that need to be funded. If the bank competes with other banks to gain deposit money, it could reduce the net outflow of funds to zero, eliminating the need to fund transfers. Or it could fund transfers by borrowing, perhaps using loans it has made as collateral. Being able to create the money that corresponds to the loans they make doesn't change the fact that overall banks do need to have a total of deposits and borrowing that matches their total lending.
The fact that banks need their books to balance helps create the illusion that they only lend money they already have, when in reality they lend (and create money) first, and work out how they are going to balance the books after the fact.
There may be reserve and capital requirements associated with making loans, which mean banks need to set aside a small fraction of the value of each loan for a rainy day. These requirements also need to be funded, but apparently these overheads are not the primary factors limiting money creation. (One of the papers linked to below describes how, when in 2008 Barclays needed 5.8 billion pounds of new capital, they created the money so it could be invested in themselves. Another wheeze is that a bank can charge an origination fee on a loan, which to the extent it covers the capital requirement means they've created the money that covers that overhead.)
The total amount of money created by banks will depend on how much customer demand there is for profitable loans. Whether a potential loan looks profitable depends on central bank interest rates, so customer demand for loans and central bank interest rates are the main two factors that determine how much money is in circulation.
Other businesses can make loans and hold customer money, but they do not create money. What distinguishes banks is that they are exempt from the general rule that customer money has to be segregated from money belonging to the business. If a stockbroker goes bust while you have cash in your account, you should get your cash back, it belongs to you and cannot be used to pay the stockbroker's debts. In contrast, the money in your bank account doesn't directly belong to you, your balance represents an amount that you have lent to the bank. If the bank goes bust, you are someone the bank owes money to, not someone it was holding money for.
Bank of England article
www.bankofengland.co.uk/-/media/boe/files/quarterly-bulletin/2014/money-creation-in-the-modern-economy.pdf
Paper investigating which theory of money is correct.
www.sciencedirect.com/science/article/pii/S1057521915001477
Paper explaining the difference between banks and other businesses.
www.sciencedirect.com/science/article/pii/S1057521914001434