Banks want your money because deposits are the cheapest raw material they have for making loans, the anchor for selling you higher-margin products, and a key ingredient in meeting the capital and liquidity rules federal regulators enforce. Every checking or savings dollar you park with a bank funds lending that earns several percentage points more than the bank pays you, opens the door to fee income and cross-selling, and strengthens the ratios examiners watch. That is why sign-up bonuses, fee waivers, and promotional rates exist: your deposit is worth far more to the institution than whatever it spends to attract you.
The Interest Rate Spread Is the Core Business
A bank’s main job is to pay depositors a low rate, lend the same money out at a higher rate, and keep the difference. The industry calls that gap the net interest margin, and it is the single largest source of revenue for most commercial banks. A typical savings account pays around 0.61% APY, while a 30-year mortgage runs roughly 6% to 7%, and commercial and personal loans go higher. The spread funds salaries, branches, technology, and shareholder returns.
That math is why a bank treats your checking balance like inventory. Every idle dollar in a zero-interest account is essentially free capital the institution can redeploy into a loan earning several points more. Banks funded largely by low-cost deposits tend to be more profitable than those relying on borrowing from other institutions, so the lifetime lending value of your account far exceeds the cost of the incentives used to open it.
Interest the bank pays you is taxable. If you earn $10 or more in interest in a year, the bank must report it to the IRS on Form 1099-INT, and you owe federal income tax on it whether or not the form reaches you.1Internal Revenue Service. About Form 1099-INT, Interest Income
One Deposit Funds Many Loans
Banks do not simply hold your cash in a vault. When you deposit $10,000, the institution keeps enough on hand to cover expected withdrawals and lends the rest to a business, homebuyer, or other borrower. That borrower spends the money, someone else deposits it, and the cycle repeats across the banking system. A single deposit can support several rounds of lending and re-depositing, expanding the total money supply well beyond the original amount.
The old textbook version of this is “fractional reserve banking,” but the mechanics have shifted. The Federal Reserve reduced the formal reserve requirement to zero percent in March 2020, and it has stayed there.2Federal Reserve Board. Reserve Requirements Banks still cannot lend without limit; capital rules, liquidity ratios, and the practical need to honor withdrawals constrain them. But the binding guardrails today are risk-based capital and the liquidity coverage ratio, not a fixed reserve percentage.
From your side, the important point is that the bank needs a steady inflow of new deposits to keep the cycle going. When depositors pull money faster than new funds arrive, the bank has to borrow from other institutions or the Fed at higher cost, and the profit margin narrows. A reliable base of retail deposits is cheaper and more stable than anything the bank can find on the wholesale market.
Fees and Cross-Selling Are the Second Revenue Stream
Lending gets the headlines, but fees are a large share of bank income. Federal Reserve data shows noninterest income has recently accounted for roughly 40% of total bank income.3Federal Reserve Bank of St. Louis. Bank Non-Interest Income to Total Income for United States That category covers service charges on deposit accounts, ATM surcharges, interchange fees on every debit card swipe, and commissions on investment and insurance products.
Once you open a checking account, the bank also gains something more valuable than your balance: a relationship. It sees your income, spending, and saving patterns, and that visibility makes it far easier to offer you a credit card, auto loan, mortgage, or brokerage account. Each additional product generates its own revenue, and customers who hold several products at one institution rarely switch. The initial deposit is less a profit center on its own than the hook that makes everything else possible.
Overdraft Fees
Overdrafts have historically been one of the largest fee categories. If your balance drops below zero and the bank covers a transaction, it typically charges a per-item fee. Federal rules require the bank to get your explicit consent before charging overdraft fees on ATM withdrawals and one-time debit card purchases; without that opt-in, those transactions are simply declined at no cost.4eCFR. 12 CFR 1005.17 – Requirements for Overdraft Services Recurring payments and checks are not covered by that opt-in rule, so the bank can still charge overdraft fees on those without separate consent. If you opted in when you opened the account and have regretted it since, you can revoke consent at any time.
Monthly Maintenance Fees
Many banks charge a monthly maintenance fee on checking accounts, commonly $5 to $15. Most waive it if you keep a minimum balance or set up a recurring direct deposit. On a small balance with no direct deposit, those fees run $60 to $180 a year, quietly eating whatever interest the account earns. Check whether your account qualifies for a waiver, or whether a no-fee account elsewhere would serve you better.
Regulators Reward Banks for Holding Stable Deposits
Banks do not chase deposits only for profit. Federal law requires large financial institutions to hold enough high-quality liquid assets to survive a 30-day stress scenario. The Federal Reserve enforces this through the liquidity coverage ratio, which mandates that a covered institution’s liquid asset buffer divided by its projected net cash outflows over 30 days must be at least 1.0 at all times.5eCFR. 12 CFR Part 249 Subpart B – Liquidity Coverage Ratio Stable retail deposits improve that ratio because regulators treat them as less likely to flee in a crisis than wholesale funding.
The Federal Reserve also runs annual stress tests that simulate a severe recession and measure whether each large bank would still have enough capital to keep operating.6Federal Reserve Board. Stress Tests Results feed into a firm-specific stress capital buffer on top of baseline requirements. If a bank falls below its total capital requirement, the consequences are automatic: restrictions on dividends, stock buybacks, and discretionary bonuses.7Federal Reserve Board. Federal Reserve Board Announces Final Individual Capital Requirements for Large Banks, Effective on October 1 Institutions that slide further face frozen asset growth, a ban on new branches, and mandatory capital restoration plans under federal prompt corrective action rules.8Office of the Law Revision Counsel. 12 USC 1831o – Prompt Corrective Action A weak deposit base leaves a bank constantly close to those thresholds, which is another reason institutions spend heavily to bring in and retain depositors.
Deposits do carry a direct cost. The FDIC charges each insured bank a quarterly assessment based on deposit volume and risk profile. Rates for well-rated established banks start at 2.5 basis points a year (about $2.50 per $10,000 in deposits) and climb sharply for riskier or newer institutions, reaching as high as 42 basis points in some categories.9FDIC.gov. FDIC Assessment Rates Banks pay the insurance bill willingly because the lending and fee income the same deposits generate is much larger.
What You Get in Return
Federal Deposit Insurance
Your deposits are protected up to $250,000 per depositor, per insured bank, per ownership category.10Office of the Law Revision Counsel. 12 USC 1821 – Insurance Funds The limit is set by federal statute and covers checking, savings, money market deposit accounts, and CDs. If you hold accounts in different ownership categories at the same bank — for example an individual account, a joint account, and a retirement account — each category is insured separately up to the ceiling.11FDIC.gov. Deposit Insurance FAQs Credit unions offer equivalent coverage through the National Credit Union Share Insurance Fund; individual, joint, and IRA or Keogh retirement accounts at federally insured credit unions are each insured up to $250,000 per member.12National Credit Union Administration. Share Insurance Coverage If your balances at one institution exceed the limits, spreading funds across banks or ownership categories is the simplest way to stay fully covered.
Identity Verification and Cash Reporting
Before a bank can accept your deposit, federal law requires it to verify who you are. Every bank must maintain a written Customer Identification Program that collects, at minimum, your name, date of birth, address, and a government identification number such as a Social Security number or taxpayer ID.13eCFR. 31 CFR 1020.220 – Customer Identification Program Requirements for Banks The bank then verifies that information using documents like a driver’s license or passport. If the bank cannot form a reasonable belief about your identity, it must refuse the account.
Once you are a customer, cash transactions above $10,000 in a single business day trigger a Currency Transaction Report to the Financial Crimes Enforcement Network.14Financial Crimes Enforcement Network (FinCEN). FinCEN Currency Transaction Report Electronic Filing Requirements The bank aggregates multiple same-day transactions, and deliberately structuring deposits to stay under the threshold is itself a federal crime. The rule exists to detect money laundering and tax evasion, and it explains some of the questions you may get when handling large amounts of cash.
Disclosures and Privacy
Federal truth-in-savings rules require the bank to hand you a written disclosure before you open a deposit account. It must state the annual percentage yield, the interest rate, any minimum balance needed to earn that yield or avoid fees, and the amount and conditions of every fee. For variable-rate accounts, the disclosure must explain how the rate is set and how often it can change. Your periodic statements must itemize every fee charged during the period and show both the dollar amount and the annualized yield of interest earned.15eCFR. 12 CFR Part 1030 – Truth in Savings (Regulation DD)
Banks also collect a considerable amount of data about your finances, and federal law gives you some control over how it is shared. Under the Gramm-Leach-Bliley Act, your bank must provide a written privacy notice at account opening and annually thereafter, describing what personal information it collects, who it shares that information with, and how it protects it.16Federal Trade Commission. How To Comply with the Privacy of Consumer Financial Information Rule of the Gramm-Leach-Bliley Act If the bank shares your nonpublic personal information with unaffiliated third parties outside narrow exceptions, it must give you a clear opt-out notice and a reasonable way to use it, such as a toll-free number or a check-box form. Requiring you to write a letter does not qualify. An opt-out stays in effect after you close the account unless you cancel it.
Read the privacy notice that comes with your account paperwork. If you would rather the bank not share your financial data with outside marketers, opt out early. Most people never do, which is what the cross-selling strategy counts on.