Money & Finance › Banks & credit › How banks create money: lending and fractional reserves
Bank runs: when depositors all want out at once
· Concept
Fact, law or dataA rule, statute, definition or measured number.
A rush of depositors pulling money from a bank at once, which can sink it even if it is basically sound.
See it on the Money & Finance map →How it works
Because a bank lends out most deposits, it cannot repay everyone at once. If depositors fear it is failing, each has reason to withdraw first, and the fear becomes self-fulfilling. About 9,000 US banks failed from 1930 to 1933. Deposit insurance largely ended runs by small savers, but large uninsured depositors still run, now by phone: Silicon Valley Bank lost $42 billion in one day in March 2023 and was closed the next morning.
Why it matters
Runs can topple sound banks and spread panic to others, which is why the Fed's discount window, FDIC insurance and bank liquidity rules exist.
Think of it like
Like every tenant giving notice at once: no building can refinance fast enough to survive sudden 90% vacancy.
Facts, rules and data
FDIC failure records; Diamond and Dybvig's 1983 model of runs, honored by the 2022 Nobel Prize; the Fed's April 2023 review of SVB's failure.
Debates and risks
Whether social media and instant mobile transfers make runs too fast for existing safeguards is debated; some propose insuring all business payment accounts.
Connections (6)
▸The discount window: lender of last resort is designed to stop Bank runs: when depositors all want out at onceFact, law or data
The connection
A run forces a bank to raise cash fast, often by dumping loans or bonds at a loss. The discount window lets a solvent bank pledge those assets to the Fed for cash instead, paying depositors without a fire sale. Ideally, knowing the backstop exists keeps depositors calm in the first place.
When and why
Federal Reserve Banks since 1914, after the Panic of 1907 showed private rescues were not enough; heavily used in 2008 and March 2023.
How we know
Discount window borrowing hit records during the 2008 crisis and again, about $153 billion, in March 2023 as runs hit regional banks.
Debates and risks
It did not save Silicon Valley Bank, which was not set up to borrow quickly; stigma and slow collateral checks remain known weak points.
▸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.
▸FDIC deposit insurance (up to $250,000) was created to prevent Bank runs: when depositors all want out at onceFact, law or data
The connection
Runs happen because depositors who get out first are paid in full. Insurance removes the reason to rush: insured deposits are safe whether withdrawn today or never. Small savers stopped lining up, and only nine insured banks failed in 1934, after about 4,000 bank failures in 1933.
When and why
Banking Act of June 1933; coverage began January 1, 1934, in the depths of the Depression's banking collapse.
How we know
FDIC failure statistics; economists Douglas Diamond and Philip Dybvig modeled how insurance prevents runs (1983), work cited in their 2022 Nobel prize.
Debates and risks
Insurance stops only insured runs. Uninsured depositors pulled $42 billion from SVB in one day in March 2023; how far coverage should extend is debated.
▸Silicon Valley Bank collapse (2023) was a digital-age case of Bank runs: when depositors all want out at onceFact, law or data
The connection
SVB's run followed the old script at new speed. Its depositors were a tight network of startups and venture firms. After the loss announcement, warnings spread on group chats and Twitter, and customers moved money by phone: $42 billion left in one day, about a quarter of deposits, with $100 billion more queued.
When and why
Santa Clara, California, March 9–10, 2023.
How we know
The Fed's April 2023 review and FDIC reports give the withdrawal figures; academic studies tied the outflows to Twitter activity.
Debates and risks
Whether deposit insurance and liquidity rules designed for slower runs can cope, and whether to insure all business payment accounts, are debated.
▸Panic of 1907 and J.P. Morgan's rescue spread as a wave of Bank runs: when depositors all want out at onceFact, law or data
The connection
The 1907 panic spread through runs. Once Knickerbocker Trust stopped paying, depositors lined up at other trust companies, fearing they were next, and banks hoarded cash. Each withdrawal forced more selling, pushing up loan rates and freezing credit nationwide, until Morgan's group stopped the runs by supplying cash to sound firms.
When and why
New York City, October 18 to early November 1907: Knickerbocker Trust, then the Trust Company of America, with runs and cash hoarding spreading to other cities.
How we know
Newspapers of the day photographed lines of depositors; bank records and the Comptroller of the Currency's reports document withdrawals and suspensions.
Debates and risks
Why trust companies were hit hardest, and whether access to the bankers' clearinghouse would have stopped the runs, is debated by economic historians.
▸GENIUS Act reserve rules: 1:1 in cash and short T-bills aim to prevent the stablecoin version of Bank runs: when depositors all want out at onceFact, law or data
The connection
A stablecoin promises $1 on demand, like a bank deposit, so fear can trigger mass redemptions. Requiring full backing in cash and short bills means an issuer can sell assets near face value and pay everyone. TerraUSD, an algorithmic token with no cash or T-bill reserves, collapsed in 2022; USDC dipped when reserves were stuck at a failed bank.
When and why
Rules written in 2025, after the 2022 TerraUSD collapse and the March 2023 USDC depeg.
How we know
Past runs show what failed; the new reserve rules have not yet been tested by a major run.
Debates and risks
Whether dumping billions of T-bills within hours during a panic would move prices, and whether the Fed would ever step in.