Money & Finance › Banks & credit
How banks create money: lending and fractional reserves
· Concept
Fact, law or dataA rule, statute, definition or measured number.
Banks create most money by lending, keeping only a fraction of deposits on hand as cash or reserves.
See it on the Money & Finance map →How it works
When a bank makes a loan, it does not hand over someone else's savings; it types a new deposit into the borrower's account, creating money. Repaying the loan destroys it. Banks keep only a fraction of deposits as cash or reserves at the Fed, betting that not everyone withdraws at once. The textbook 'money multiplier' says reserves limit lending, but with reserve requirements at zero since 2020, the real limits are capital rules, profitability and loan demand.
Why it matters
It explains why most money is bank deposits rather than paper cash, and why credit booms and busts swell and shrink the money supply.
Think of it like
Like a garage selling 120 monthly passes for 100 spaces: it works because not everyone parks at once.
Facts, rules and data
The Bank of England's 2014 paper 'Money creation in the modern economy'; Fed money-supply data; the Fed's March 2020 cut of reserve requirements to zero.
Debates and risks
How much reserves still constrain lending is debated, as is whether 'full-reserve' banking, like the 1930s Chicago Plan, would be safer.
Inside this (4)
Connections (7)
▸What money is: a shared, transferable claim is mostly created through How banks create money: lending and fractional reservesFact, law or data
The connection
If money is a transferable claim everyone accepts, a bank deposit qualifies, and most modern money is exactly that. Banks create those claims when they make loans, crediting borrowers' accounts. Paper currency is a small minority; the rest exists as entries on bank ledgers.
When and why
From goldsmiths' deposit receipts in 1600s London to today's deposit accounts; spelled out by the Bank of England in 2014.
How we know
Fed data show currency is about $2.4 trillion of M2's roughly $22 trillion in 2025; most of the rest is bank deposits.
Debates and risks
Whether bank deposits are truly money or only promises of money is an old debate, sharpened today by stablecoins and digital currencies.
▸Commercial banks: taking deposits, making loans operate on How banks create money: lending and fractional reservesFact, law or data
The connection
A bank's business model is fractional reserve banking: it keeps a slice of deposits as liquid reserves and makes loans that run for years at higher rates. Each new loan creates a matching deposit. The bank profits from the spread but must keep enough cash and capital to survive withdrawals and losses.
When and why
Practiced since Renaissance Italy and 1600s London goldsmiths; US reserve rules began in 1863 and were cut to zero in March 2020.
How we know
Bank balance sheets in FDIC call reports show loans far exceeding the cash and reserves on hand.
Debates and risks
Whether post-2008 liquidity rules are enough when deposits can leave in hours, as at Silicon Valley Bank, is debated.
▸How banks create money: lending and fractional reserves makes banks vulnerable to Bank runs: when depositors all want out at onceFact, law or data
The connection
Because only a fraction of deposits is held as cash and loans cannot be called in quickly, a bank cannot pay everyone at once. If depositors suspect trouble, withdrawing first is the rational move, and the rush itself can sink a solvent bank.
When and why
Runs date back to medieval and early modern banking; US waves struck in 1837, 1873, 1893, 1907 and 1930–33.
How we know
Diamond and Dybvig's 1983 model formalized the mechanism; FDIC data show runs by small savers nearly vanished after deposit insurance began in 1934.
Debates and risks
Whether runs are pure panic or informed depositors spotting real losses, as with SVB's underwater bonds, is debated.
▸How banks create money: lending and fractional reserves is mimicked outside banks by Shadow banking: credit outside the banking systemMainstream view
The connection
Banks fund long loans with deposits payable on demand. Shadow banks copy the trick: money funds offer $1 shares on demand while holding short-term paper, and dealers fund bonds with overnight repo. Without deposit insurance or routine Fed loans, they are exposed to runs the way banks were before 1934.
When and why
Grew from the 1970s with money funds and securitization; by 2007 US shadow-bank liabilities, roughly $20 trillion, exceeded traditional banks', per a 2010 New York Fed study.
How solid is the link?
Zoltan Pozsar and colleagues mapped the system for the New York Fed (2010); Gary Gorton and Andrew Metrick documented the 2007–08 'run on repo'.
Debates and risks
Whether shadow banks should get bank-style rules, a Fed backstop, or neither is unresolved; the 2008 and 2020 rescues of money funds widened the safety net anyway.
▸How banks create money: lending and fractional reserves creates most of The money supply: M0, M1, M2 and M3Fact, law or data
The connection
When a bank makes a loan, it credits the borrower's account with a new deposit, and that deposit is money. Most of M2 consists of such deposits, created by lending and destroyed as loans are repaid. Printed cash is only about a tenth.
When and why
Modern banking since the goldsmith-bankers of 1600s London; described for today's system by the Bank of England in 2014.
How we know
Bank balance sheets and Fed data; the Bank of England's 2014 paper 'Money creation in the modern economy' explains the mechanism.
Debates and risks
Whether bank lending is limited mainly by reserves, capital rules or loan demand is argued; most central banks now say capital and demand.
▸Reserve requirements (cut to zero in 2020) were the 'fraction' in How banks create money: lending and fractional reservesFact, law or data
The connection
In the textbook, a 10% requirement means a $100 deposit lets the bank lend $90, which is redeposited and lent again, multiplying into $1,000 of deposits. In reality banks lend first and find reserves after, the Fed supplies reserves to hold its rate target, and capital is the binding limit. The zero requirement since 2020 made that official.
When and why
Requirements date to the National Bank Act of 1863; the Fed cut them to zero effective March 26, 2020.
How we know
The Fed's 2020 announcement; the Bank of England's 2014 paper 'Money creation in the modern economy' explains why the multiplier story misleads.
Debates and risks
Some economists say reserves still constrain lending at the margin; others say the multiplier never described how banks actually worked.
▸Flow of funds: the Fed's Z.1 map of who owes what to whom records the deposits created by How banks create money: lending and fractional reservesFact, law or data
The connection
When a bank makes a loan it credits the borrower's account, creating a new deposit. Z.1 records both sides: the loan as a bank asset and the deposit as a bank liability, which appears again as a household or business asset. That lets analysts trace money creation sector by sector.
When and why
In Z.1 tables for depository institutions and for checkable and time deposits, quarterly since 1955.
How we know
Z.1 bank tables reconcile with bank call reports; the Bank of England's 2014 paper 'Money creation in the modern economy' describes the mechanism.
Debates and risks
Reserve requirements have been zero since March 2020, so what really limits lending, capital rules or loan demand, is debated.