Banks pay interest on savings accounts because your deposit doesn’t sit in a vault — it funds the bank’s lending business. Every dollar you deposit gets loaned out to homebuyers, small businesses, and consumers at rates far higher than the bank pays you, and the gap between the two is where the bank makes most of its money. The interest credited to your account is essentially rent the bank pays for the use of your cash. With the national average savings rate at 0.39% as of early 2026, that rent can feel small, but it’s the mechanism that keeps the whole arrangement working for both sides.
What the Bank Does With Your Deposit
When you deposit money, the bank records it as a liability — money it owes you — and then puts that money to work. Your deposit, pooled with millions of others, funds mortgages, auto loans, small business loans, personal loans, and credit lines. Borrowers pay interest on those loans at rates well above what you earn on savings.
Banks also route a portion of deposits into low-risk securities like U.S. Treasury bonds and municipal bonds. Those don’t produce as much revenue as loans, but the income is steady and the default risk is close to zero. The mix between lending and securities shifts with market conditions and loan demand.
The engine driving all of this is the net interest margin: the spread between what the bank earns on its loans and investments and what it pays out to depositors. If a bank charges 7% on a mortgage and pays you 0.4% on your savings, that 6.6% spread, minus operating costs, is the bank’s profit. Interest paid to you is the cost of keeping the deposit base that funds the loans.
Federal tax law treats the interest a bank pays depositors as interest on indebtedness, which makes it deductible as a business expense.1Office of the Law Revision Counsel. 26 USC 163 – Interest That deduction pulls the bank’s effective cost of your deposit down even further, which is one reason the arrangement remains profitable for the bank even when it’s paying more competitive rates.
Why the Rate You Get Is What It Is
The biggest force behind your savings rate is the federal funds rate set by the Federal Reserve’s Federal Open Market Committee. This is the rate banks charge each other for overnight lending, and as of March 2026 the FOMC’s target range sits at 3.50% to 3.75%.2Federal Reserve Economic Data. Federal Funds Target Range – Upper Limit Changes in that rate move through short-term interest rates, mortgage rates, and eventually the rate your bank offers on savings.3Board of Governors of the Federal Reserve System. Economy at a Glance – Policy Rate
When the Fed raises its target, banks face higher borrowing costs and nudge savings rates up to keep attracting the deposits they need. When the Fed cuts, banks follow in the other direction, usually faster on the way down than on the way up, because lowering what they pay you goes straight to margin.
Competition matters just as much as Fed policy, and it’s where the biggest gaps between banks show up. Online-only banks have no branch overhead, so they can consistently pay several times the national average. Traditional brick-and-mortar banks carry real estate and staffing costs and tend to lag. The FDIC-reported national average sits at 0.39%, while high-yield online accounts commonly offer rates above 4%.4Federal Deposit Insurance Corporation. National Rates and Rate Caps That spread is one of the largest easy wins in personal finance.
Inflation quietly shapes the picture too. If a bank pays 0.4% while inflation runs at 3%, your purchasing power drops about 2.6% per year. Banks offering higher rates can market the appeal of at least staying closer to breakeven, which helps them pull in deposits from rate-conscious savers.
What Limits How Much a Bank Can Pay You
Banks don’t keep all your deposits on hand. The Federal Reserve reduced reserve requirements to zero in March 2020, so there’s no legal mandate to hold any specific fraction of deposits in reserve.5Board of Governors of the Federal Reserve System. Reserve Requirements In practice, banks still hold cash and liquid assets to cover daily withdrawals, check clearing, and electronic transfers, but they size that buffer themselves based on risk management rather than a regulatory floor.
The size of that buffer affects what a bank can pay. Every dollar sitting in cash to cover withdrawals is a dollar not earning revenue through lending. Banks with leaner buffers have more money deployed in loans and can theoretically afford higher savings rates, though they also carry more risk if withdrawals spike.
Separate from liquidity, federal regulations require banks to hold capital against their risk-weighted assets.6eCFR. 12 CFR Part 217 Subpart D – Risk-Weighted Assets, Standardized Approach A loan to a risky borrower requires more capital than a U.S. Treasury bond, which carries a zero percent risk weight.7National Credit Union Administration. Risk Weights at a Glance Those requirements cap how aggressively a bank can lend, which in turn caps the revenue available to fund higher deposit rates.
How the Interest Reaches Your Account
Banks express savings rates as an annual percentage yield, or APY, which accounts for compounding. Compounding is the process of earning interest on previously earned interest. When a bank advertises 4.5% APY, that’s what you’d earn over a full year with interest compounding at whatever frequency the bank uses, not a flat 4.5% of your balance.
Most banks compound interest daily or monthly. Daily compounding earns slightly more because each day’s interest gets folded into the balance sooner and starts generating its own interest sooner. On a $10,000 deposit at the same stated rate, the difference between daily and monthly compounding amounts to only a few dollars a year, but it widens with larger balances and longer time horizons.
When comparing accounts, compare APY rather than the stated interest rate. APY already builds in the compounding frequency, so it gives you a clean side-by-side number. Two banks can advertise the same nominal rate and deliver different APYs because one compounds daily and the other monthly.
What You Owe on the Interest You Earn
Any interest you earn in a savings account is taxable income in the year you earn it, whether or not you withdraw it. Banks are required to send you a Form 1099-INT if they pay you $10 or more in interest during the year.8Internal Revenue Service. About Form 1099-INT, Interest Income Even if you earn less than $10 and never get a form, the interest is still reportable on your return.9Internal Revenue Service. Topic No. 403, Interest Received
The IRS is explicit that you must report all taxable interest income even without a Form 1099-INT.10Internal Revenue Service. Publication 550, Investment Income and Expenses Amounts under $10 rarely draw enforcement attention, but the obligation is there. For anyone earning meaningful interest in a high-yield account, the 1099-INT arrives by late January and is straightforward to report.
The Principal Is Safe Even When the Interest Is Small
The rate might be modest, but the money itself is protected. The Federal Deposit Insurance Corporation insures deposits at commercial banks up to $250,000 per depositor, per insured bank, for each ownership category.11Federal Deposit Insurance Corporation. Your Insured Deposits Coverage applies to savings accounts, checking accounts, money market deposit accounts, and CDs. Credit union deposits receive the same $250,000 coverage through the National Credit Union Administration’s Share Insurance Fund.12National Credit Union Administration. Share Insurance Coverage
The coverage extends to principal and any accrued interest up to the limit. Deposits at multiple banks are insured separately, so $250,000 at Bank A and $250,000 at Bank B gives you $500,000 in total coverage. Within a single bank, different ownership categories (individual, joint, retirement, trust) each receive their own $250,000 limit.
Investment products your bank may sell alongside deposit accounts — stocks, bonds, mutual funds, annuities, crypto assets, life insurance — are not covered by deposit insurance, even when purchased through the bank.11Federal Deposit Insurance Corporation. Your Insured Deposits Those carry investment risk that deposit insurance was never designed to cover. The interest arrangement that pays you a small return on a savings account also comes with the assurance that the underlying dollars are backed by the federal government up to the coverage limit.