When you deposit money into a savings account, you are effectively lending the bank your cash. In return, the bank pays you interest—often very little. As of mid-2026, the average savings account yield in the United States sits at roughly 0.5%, according to FDIC data. Meanwhile, the average 30-year fixed mortgage rate hovers near 7%. That gap—the spread between what the bank pays you and what it charges a borrower—is how banks make a significant portion of their profit. This article follows the money from your deposit to the mortgage closing table, examining the costs, risks, and regulatory constraints that shape that spread.

The Savings Account Is a Loan to the Bank

Every dollar in a savings account is a liability on the bank's balance sheet. The bank owes that dollar back to you, but in the meantime, it can lend that dollar out at a higher rate. This is the core of banking: maturity transformation. Deposits are typically short-term or demandable, while mortgages are long-term assets. The bank profits from the difference between the interest it earns on loans and the interest it pays on deposits.

The average savings yield of 0.5% is a national blended figure; large brick-and-mortar banks often pay even less—some as low as 0.01%—while online banks and credit unions may offer 4% to 5% on high-yield savings accounts. But the vast majority of deposits sit in low-yield accounts at large banks. As of late 2024, the Federal Deposit Insurance Corporation reported that roughly 60% of domestic deposits were in accounts yielding less than 1%.

That 0.5% cost of funds is incredibly cheap compared to the roughly 7% mortgage rate. The spread of about 6.5 percentage points is not pure profit, however. Banks must set aside a portion for loan loss reserves—typically around 1% to 2% of the loan portfolio—to cover defaults. They also have overhead: branch rent, employee salaries, technology, and marketing. Still, after those costs, the net interest margin—the difference between interest income and interest expense relative to earning assets—averaged roughly 3.3% in the first quarter of 2026, according to FDIC data.

There is also a risk concept known as a haircut. In finance, a haircut is the discount applied to the value of an asset when used as collateral. For banks, deposit insurance via the FDIC effectively gives depositors a haircut on risk: your deposit is insured up to $250,000, so you bear little credit risk. The bank, in turn, can use those insured deposits as a stable funding source with a lower regulatory capital charge than uninsured deposits or wholesale funding. That implicit subsidy further widens the spread.

How Banks Price the Spread Between Deposits and Mortgages

Banks set mortgage rates based on several factors: the cost of funds, the risk of default, operating expenses, and the desired profit margin. The cost of funds is largely driven by deposit rates, but also by wholesale borrowing like Federal Home Loan Bank advances or issuing bonds. For community banks, deposits are the primary funding source, making the spread especially sensitive to local competition for deposits.

The net interest margin (NIM) is the key metric. In Q1 2026, the industry average NIM was about 3.3%, but that varies widely. Community banks often have higher NIMs because they rely more on core deposits—checking and savings accounts that pay very little—and lend at higher rates to small businesses and consumers. Larger banks may have lower NIMs but make up for it with fee income and scale.

Regulatory actions can also affect the spread. In May 2026, the Federal Reserve Board issued enforcement actions against a former employee of Atlantic Union Bank and a former employee of Frost Bank. While the specifics involve individual misconduct, such cases remind banks that compliance failures carry legal costs and reputational risk, which ultimately get priced into lending margins. Banks may widen spreads to build a buffer against potential fines or litigation.

The Fed's discount rate also plays a role. The minutes from the April 20 and 29, 2026 discount rate meeting, released on May 26, 2026, noted that inflation remained somewhat sticky. The discount rate is the rate at which banks can borrow directly from the Fed for short-term needs. When the discount rate is high, it signals tighter monetary policy, which pushes up short-term rates and can narrow the spread if banks raise deposit rates faster than mortgage rates adjust.

Deposit Costs Are Sticky Even When Rates Rise

When the Federal Reserve raises interest rates, banks are often slow to increase savings yields. This stickiness is a deliberate strategy: banks prefer cheap core deposits over more expensive certificates of deposit (CDs) or money market accounts. As of April 2026, the Fed's discount rate meeting highlighted that inflation remained above the 2% target, suggesting rates could stay higher for longer. Yet many large banks continue to pay near-zero yields on standard savings accounts.

According to a 2025 study by the Consumer Financial Protection Bureau, the average large bank paid 0.3% on savings accounts, while online banks averaged 4.5%. That gap of over 4 percentage points represents a significant transfer of wealth from savers to bank shareholders. The CFPB estimated that if all deposit accounts paid the online bank rate, savers would earn an additional $150 billion annually.

Why don't savers switch? Switching costs—both monetary and psychological—keep many accounts in place. There is the hassle of opening a new account, updating direct deposit and automatic payments, and the risk of a temporary loss of access to funds. Some banks also charge early account closure fees, which can reach $50 if you close an account within 90 to 180 days of opening. Those fees act as a barrier to switching, effectively locking savers into low-yield accounts.

Community banks and credit unions sometimes offer more competitive rates, but they may have geographic restrictions or membership requirements. The result is a fragmented market where the spread between deposit costs and mortgage rates remains wide, benefiting banks that can attract and retain low-cost deposits.

The Hidden Fee Structure That Boosts the Margin

Beyond the interest spread, banks generate significant income from fees tied to deposit accounts. Monthly maintenance fees average around $15 per account, according to Bankrate data from 2025. Overdraft fees, which hit a median of $34 per incident in 2025 according to the CFPB, add another layer. These fees are lucrative because they are often paid by the least sophisticated customers—those who carry low balances and are more likely to overdraw.

Early account closure fees, as mentioned, can reach $50. Some banks also charge fees for excessive withdrawals, paper statements, or using out-of-network ATMs. The sum of these fees, often called non-interest income, can equal roughly 10% of net interest margin for a typical bank. In effect, the bank earns a spread on your deposits and also charges you for the privilege of holding them.

The fee structure is not always transparent. A 2024 study by the Pew Charitable Trusts found that many bank disclosures bury fee schedules in dense fine print. Customers may not realize that a "free checking" account comes with a $12 monthly fee unless they maintain a minimum balance of $1,500. Similarly, savings accounts may have monthly fees if the balance falls below a threshold.

These fees fund branch operations, marketing, and technology upgrades. But they also create a perverse incentive: banks have little reason to raise savings yields if they can extract revenue from fees instead. For a saver with a $5,000 balance, a $15 monthly fee wipes out any interest earned at a 0.5% yield, turning the account into a net cost.

Regulatory Constraints That Shape Lending Margins

Banks operate under a web of regulations that directly affect the spread. Capital requirements, set by the Basel III framework and enforced by U.S. regulators, force banks to hold a certain percentage of risk-weighted assets as equity. For a mortgage loan, that capital charge is typically around 4% to 6% of the loan amount, depending on the loan-to-value ratio and other factors. That capital cannot be lent out, so banks must earn enough spread to generate a return on that capital.

The haircut concept applies here as well. When banks securitize mortgages into mortgage-backed securities (MBS), they often have to apply a haircut—a discount to the market value—when using those securities as collateral for borrowing. This haircut reflects the risk that the MBS could lose value. Higher haircuts mean banks need more equity to support the same amount of lending, which can compress the spread or force banks to charge higher mortgage rates.

Enforcement actions, like the one against Atlantic Union Bank in May 2026, add compliance costs. Banks must invest in monitoring systems, legal staff, and internal controls to prevent misconduct. The Fed's action against a former employee of Atlantic Union Bank for alleged violations of law or regulation likely resulted in fines and remediation costs that are passed on to customers in the form of wider spreads.

The discount rate meeting minutes from April 2026 also hinted at the Fed's concern about inflation persistence. If the Fed keeps rates high, banks' cost of wholesale funding rises, which can narrow the spread if deposit costs eventually catch up. But because deposit rates are sticky, the spread often widens in the early stages of a rate hike cycle and narrows later as competition for deposits intensifies.

Who Wins When Savers Stay Put

The primary beneficiaries of the wide spread between savings yields and mortgage rates are bank shareholders. Higher net interest margins translate into higher profits and, often, higher stock prices. For large banks with trillions in deposits, even a 0.1% increase in NIM can mean billions in additional annual income.

Mortgage borrowers, on the other hand, pay higher rates because banks can fund loans cheaply via deposits but choose not to pass on the savings. If deposit costs were higher, mortgage rates might be lower, all else equal. But banks have little incentive to raise deposit rates when savers are slow to switch. The result is a transfer of wealth from borrowers and savers to bank shareholders.

Savers lose purchasing power to inflation. With inflation running around 3% as of mid-2026, a 0.5% savings yield means a real loss of 2.5% per year. Over a decade, that erodes a significant portion of savings. Fintechs like Betterment and Wealthfront have tried to capture this market by offering high-yield cash accounts with rates near 4.5%, but they still represent a small fraction of total deposits.

Regulatory nudges toward rate transparency have been slow. The CFPB has proposed rules requiring banks to disclose annual percentage yields more prominently, but industry lobbying has delayed implementation. Until then, the onus is on savers to shop around, and on borrowers to negotiate mortgage rates with competing offers.

Practical Takeaways for Savers and Borrowers

For savers, the most impactful step is to compare high-yield savings accounts at least once a quarter. Online banks and credit unions often offer rates 4 to 5 percentage points higher than large brick-and-mortar banks. Before opening an account, check the fee schedule: avoid accounts with monthly maintenance fees above $5, and be aware of early closure fees that could trap you.

For borrowers, mortgage rates are not set in stone. Get quotes from at least three lenders—including a credit union and an online lender—and be prepared to negotiate. Even a 0.25% reduction in rate can save thousands over the life of a loan. Also consider the total cost of the loan, not just the rate: origination fees, points, and closing costs can add up.

Understanding the Fed's discount rate signals can help you time rate decisions. When the Fed signals a rate cut, mortgage rates may fall, but deposit rates will likely drop faster. Conversely, when rates are rising, locking in a fixed-rate mortgage can protect against future increases. For savings, consider laddering CDs to capture higher rates if you expect rates to rise further.

Finally, be aware of account closure fees before opening a savings account. If you plan to switch accounts to chase a better rate, choose an institution that does not charge an early closure fee, or wait until the penalty period expires. The same caution applies to checking accounts with sign-up bonuses that require keeping the account open for a minimum period.

This article is for informational purposes only and does not constitute personalized financial advice. Consult a qualified professional for advice tailored to your individual circumstances.