Banks create money by making loans. When a bank approves a mortgage, a car loan, or a business line of credit, it does not hand the borrower cash that some saver deposited earlier. It types a new balance into the borrower’s account and books the loan as an asset on its own ledger. That new deposit is money that did not exist a moment before. This is how banks create money in the modern economy, and it is the dominant source of new dollars in circulation.
Research from the Federal Reserve Bank of Philadelphia covering 2001 through 2020 found that roughly 92 percent of deposits in the banking system came from lending activity rather than customers walking in with cash.1Federal Reserve Bank of Philadelphia. How Banks Use Loans to Create Liquidity The remaining 8 percent came from physical cash deposits. Most of the money you use, spend, and save into existence originated as somebody else’s loan.
What Happens on the Bank’s Books
Picture a bank approving a $300,000 mortgage. Two entries appear at the same moment. On the asset side, the bank records a $300,000 loan receivable from the borrower. On the liability side, it credits the borrower’s checking account with $300,000. No other customer’s balance falls. No vault is opened. The bank’s balance sheet has simply grown by $300,000 on both sides.
The borrower then spends the money. The seller of the house deposits the payment at their own bank. Total deposits in the banking system are $300,000 larger than they were before the loan closed. If the borrower eventually pays the mortgage down, the process runs in reverse: the loan asset shrinks, and the deposit money used to make the payment is extinguished. Repayment destroys money in the same way lending creates it.
This power is real, but it is not unlimited. Every loan a bank writes is also a risk it has taken on. If the borrower defaults, the bank absorbs a real loss against its own capital. That tension between lending profit and default risk is one of the forces that keeps credit creation from running away, and the rest are legal and regulatory.
Why the Textbook Money Multiplier Is Wrong
Older economics textbooks describe money creation through a “money multiplier.” A bank receives $1,000 in cash, keeps 10 percent as required reserves, lends out $900, and that $900 gets redeposited at another bank, which lends $810, and so on. The original $1,000 supposedly supports $10,000 in total deposits.
The Federal Reserve Bank of St. Louis has called this an “outdated concept,” noting that large banks had been sidestepping reserve requirements for years through overnight sweep programs even before the requirements themselves went away.2Federal Reserve Bank of St. Louis. Teaching the Linkage Between Banks and the Fed: R.I.P. Money Multiplier With reserve requirements now at zero, the multiplier equation cannot even be calculated.
More importantly, the story gets the causation backwards. Banks do not wait for deposits and then lend out a fraction of them. They originate a loan when they find a creditworthy borrower, and the deposits appear as a byproduct of that lending. Reserves get sorted out afterward through the interbank market and the Fed.
What Actually Limits How Much a Bank Can Create
Reserve Requirements Are Now Zero
Under 12 U.S.C. ยง 461, the Board of Governors of the Federal Reserve can set reserve requirements on transaction accounts anywhere from zero to 14 percent, and on nonpersonal time deposits from zero to 9 percent.3Office of the Law Revision Counsel. 12 USC 461 – Reserve Requirements Reserves must be held as vault cash or as balances at a Federal Reserve Bank.4eCFR. 12 CFR Part 204 – Reserve Requirements of Depository Institutions (Regulation D)
Since March 26, 2020, the Board has set those ratios to zero percent for every depository institution.5Federal Reserve Board. Reserve Requirements Banks are no longer legally required to hold any specific fraction of deposits in reserve. They still hold reserves voluntarily because they need them to settle payments with other banks and because the Fed pays interest on them.
Capital Requirements Are the Binding Constraint
With reserves out of the picture, capital adequacy is what actually limits how much a bank can lend. Capital requirements force a bank to fund a portion of its assets with shareholders’ equity, so that if loans go bad, equity absorbs the losses before depositors do.
Under the Federal Reserve’s framework, every bank must maintain a minimum Common Equity Tier 1 (CET1) ratio of 4.5 percent of risk-weighted assets, a Tier 1 ratio of at least 6 percent, and a total capital ratio of at least 8 percent.6Federal Reserve Board. Annual Large Bank Capital Requirements Risk-weighting matters: a Treasury bond counts for less than an unsecured consumer loan, so the same dollar of lending eats different amounts of capital depending on where it goes. A bank with $1 billion in risk-weighted assets needs at least $45 million in common equity behind them.
Large banks carry more. A stress capital buffer set through annual supervisory stress tests adds at least 2.5 percentage points on top of the CET1 minimum, and global systemically important banks face a further surcharge of at least 1.0 percent. The biggest U.S. banks effectively run above 10 percent CET1. When capital ratios drift toward the floor, regulators can restrict dividends, buybacks, and new lending until the cushion is rebuilt.
This is where credit creation hits its practical ceiling. Each new loan expands risk-weighted assets, and each expansion needs proportional capital behind it. A bank that has used up its capital headroom cannot keep lending no matter how many good borrowers walk in.
How the Fed Steers the Pace
The Fed no longer influences credit creation by adjusting the quantity of reserves. Under the “ample reserves” framework formalized in 2019, it steers short-term interest rates using two administered rates.7Federal Reserve Bank of St. Louis. The Fed’s Balance Sheet and Ample Reserves
The first is the interest on reserve balances (IORB) rate, set by the Board of Governors. It is the interest the Fed pays banks on the reserves they hold at the Fed.8Federal Reserve Board. Interest on Reserve Balances (IORB) Frequently Asked Questions No bank will lend to another bank for less than it can earn risk-free from the Fed, so the IORB rate anchors the floor of the interbank market. As of early 2026 the IORB rate is 3.65 percent, consistent with a federal funds target range of 3.50 to 3.75 percent.9Federal Reserve Board. Interest on Reserve Balances
The second is the overnight reverse repurchase agreement (ON RRP) facility, which lets money market funds and other non-bank institutions park cash with the Fed at a set rate.10Federal Reserve Board. Overnight Reverse Repurchase Agreement Operations Those counterparties then have no reason to lend overnight for less. Together the IORB and ON RRP rates keep the federal funds rate inside the target range the FOMC announces after each meeting.
When the Fed raises these rates, borrowing gets more expensive throughout the economy. Business expansion loans, mortgages, and car loans all cost more, loan demand cools, and the pace of credit creation slows. When the Fed cuts, borrowing gets cheaper and a wider pool of borrowers becomes profitable for banks to serve. Open market operations still happen, but they now manage the overall level of reserves to keep it “ample” rather than aiming at a precise quantity each day.11Federal Reserve Bank of St. Louis. How the Fed Implements Monetary Policy with Its Tools The discount window remains a backstop, with the primary credit rate currently at 3.75 percent.12Federal Reserve Bank of St. Louis. Discount Window Primary Credit Rate (DPCREDIT)
Other Brakes on the Process
Capital rules and Fed policy set the outer frame. Several other forces do real work inside it.
- Borrower demand. A bank can only create money when a creditworthy borrower wants to borrow. In recessions, households and businesses pull back even when rates fall, which is why rate cuts alone sometimes fail to revive lending.
- Risk appetite. When banks expect defaults to rise, they tighten standards, demand more collateral, and approve fewer loans regardless of how much capital they have.
- Currency leakage. When borrowers take loan proceeds as physical cash and hold it outside the banking system, that money cannot circulate through further deposits or support further lending.
- Liquidity rules. Post-crisis regulations require large banks to hold enough high-quality liquid assets to survive 30 days of financial stress and to fund long-term assets with stable funding sources.
- Deposit insurance and market discipline. The FDIC insures deposits up to $250,000 per depositor per institution, which keeps most depositors calm and lets banks lend confidently. Large uninsured depositors still watch bank health closely and provide a layer of market discipline.13Federal Reserve Bank of New York. Banks Runs and Information
A Note on Non-Bank Lenders
Mortgage companies, finance companies, and investment funds also originate loans, but they do not create deposits the way chartered banks do. They fund lending by raising capital and, heavily, by packaging loans into securities and selling them to investors, which returns the cash they need to write the next round of loans.14Office of the Comptroller of the Currency. Securitization This expands credit available to borrowers without adding to the deposit money supply the same way bank lending does. If you are trying to understand where new dollars in bank accounts come from, this channel sits alongside the banking system rather than inside it.
When Credit Creation Runs Too Hot
Credit creation makes a modern economy work, but too much of it too fast tends to inflate asset prices, especially in housing and equities. The global financial crisis was triggered in large part by a housing crash that followed years of loose mortgage lending.15Federal Reserve Bank of Chicago. Asset Price Bubbles: What Are the Causes, Consequences, and Public Policy Options
Bubbles are hard to identify while they are forming, because rising prices might reflect genuine value or unsustainable speculation, and the difference usually becomes clear only after the fall. That is why regulators focus on the inputs to credit creation, keeping capital requirements strong, supervising lending standards, and running stress tests, rather than trying to call the next crash. When the process itself is disciplined, the money banks create through lending does what it is supposed to do: finance real activity without setting up the next collapse.