How Systemic Banks Can Quietly Influence Interest Rates

Central banks try to prevent financial instability while controlling inflation. New research suggests those goals can conflict in a surprising way: protecting banks from rate shocks may encourage the largest institutions to take positions that make future monetary tightening harder.

Interest rates are normally presented as a response to inflation, employment, and economic growth. Yet monetary policymakers must also consider what a sudden rate change could do to banks holding trillions of dollars in bonds, loans, and other rate-sensitive assets.

A new study by Giampaolo Bonomi and Ali Uppal examines what happens when large banks understand that concern and adjust their portfolios accordingly.¹ Their model identifies an uncomfortable feedback loop. A central bank may accommodate vulnerable banks to avoid a crisis, but the expectation of accommodation can give those banks an incentive to remain exposed. The resulting fragility can pull interest rates away from the level justified by inflation and economic activity.

Banks do not directly dictate monetary policy. Instead, systemic importance can become indirect policy leverage.

How Financial Stability Can Distort Interest Rate Policy

The study begins with a familiar problem. Banks select portfolios before knowing exactly where interest rates will land. If rates differ sharply from their expectations, they can suffer valuation losses or face expensive portfolio adjustments. The central bank recognizes that sufficiently large losses could threaten the financial system.

That concern gives policymakers a reason to move gradually. Even when economic conditions support a larger increase, a smaller adjustment may reduce the danger of destabilizing institutions that prepared for lower rates.

The problem emerges when banks anticipate that restraint. If a systemically important institution’s losses could spread through credit markets, payment systems, or other banks, its balance sheet becomes relevant to public policy.

According to the model, banks that prefer lower rates may tilt their portfolios toward positions that become more vulnerable when rates rise. This makes higher rates more expensive for the central bank to impose, pulling policy toward the banks’ preferred outcome without explicit coordination.

The Hidden Cost of Forward Guidance

Forward guidance is intended to reduce uncertainty. Central banks communicate their likely policy direction so households, companies, and financial institutions can prepare. Investors can see one formal version of these expectations in the Federal Reserve dot plot, although those projections are not binding commitments.

The paper shows why guidance becomes more complicated when its audience is strategic. If a central bank privately expects higher rates and communicates that expectation clearly, banks can align their portfolios with the coming decision. That reduces surprise losses and supports stability.

However, banks can also use the information to choose exposures that make the announced policy costly to implement. Policymakers therefore have an incentive to overstate the likelihood of higher rates, encouraging banks to protect themselves even if less tightening is expected.

Banks understand that incentive, so they discount the message. This creates what the researchers call a responsiveness-credibility trade-off: the more willing the central bank is to accommodate bank exposures after portfolios are set, the less credible its earlier communication becomes.

The practical consequences extend beyond banks. Unreliable guidance can increase volatility across:

• Government bonds and interest-rate futures
• Bank shares and credit spreads
• Mortgage and corporate borrowing costs
• Rate-sensitive technology and growth stocks

Recent disagreement within the Federal Reserve illustrates why investors must separate an unchanged decision from the debate behind it. Securities.io reported that three policymakers favored a rate increase at the July 2026 meeting, even though the committee held its target range steady. A headline decision can therefore conceal a much wider distribution of possible future outcomes.

What the 2023 Banking Crisis Revealed

The paper uses the failures of Silicon Valley Bank and Signature Bank as a case study. It does not claim either bank intentionally assumed risk to force lower rates. Instead, it asks whether banking stress caused the Federal Reserve to raise rates by less than it otherwise would have.

Silicon Valley Bank had accumulated substantial interest-rate exposure and did not adequately hedge it. Rising rates reduced the value of its securities, while its concentrated base of uninsured depositors made it vulnerable to a rapid run. The Federal Reserve’s inspector general later concluded that the bank failed to manage its interest-rate and liquidity risks effectively, while supervisors did not escalate their concerns quickly enough through stronger supervisory action.

The study compares the Fed’s response with a Taylor rule, market expectations, and the central bank’s own minutes. All three indicate that financial instability weighed on the March 2023 decision.

The March 2023 FOMC minutes provide the clearest connection. Some participants indicated that persistent inflation and strong economic data could have justified a 50-basis-point increase without the banking-sector turmoil. The Fed instead raised its target range by 25 basis points.

This evidence is consistent with the model, but it is not proof of causation. Taylor rules depend on their inputs, and futures prices can change for several reasons. The case nevertheless demonstrates the mechanism: once financial fragility becomes severe enough, the rate required for price stability may no longer be the only relevant rate.

Why Bank Concentration Matters

The distortion becomes stronger when the banking system is concentrated. A small bank cannot normally affect national monetary policy through its portfolio choices because its failure is unlikely to destabilize the entire system. A very large or highly interconnected bank is different.

As banks consolidate, each surviving institution accounts for a larger share of systemic risk. The paper predicts that major banks’ interest-rate exposures should explain some policy variation that inflation and output alone cannot.

This reframes “too big to fail.” Systemic importance may influence policy before failure occurs, with a more accommodating rate path protecting vulnerable balance sheets even without a direct rescue.

Capital requirements, liquidity rules, stress tests, and supervision can reduce the probability that monetary policy must compensate for poor portfolio construction. Interest rates can then target inflation and employment, while prudential regulation addresses bank resilience.

What Investors Should Watch

For investors, the most useful lesson is that monetary policy cannot always be inferred from inflation data alone. When bank balance sheets are under pressure, financial stability can become an unofficial additional mandate.

Signals worth monitoring include unrealized securities losses, deposit concentration, short-term funding, hedging activity, discount-window borrowing, and credit spreads. Investors should also compare official guidance with market-implied probabilities. A widening gap can expose constraints not fully reflected in public forecasts.

Communication quality matters as much as the projected rate. Shifting guidance may reflect an effort to prevent institutions from building positions around commitments that could become difficult to honor.

Investing in Interest Rate Market Infrastructure

The paper’s case study relies partly on probabilities derived from 30-day Federal Funds futures. That creates a natural connection to CME Group, which operates major futures and options markets and provides the widely followed FedWatch Tool.

CME Group does not depend on correctly predicting rate direction. It supplies infrastructure through which institutions hedge, trade, and express expectations. Its interest-rate contracts help participants manage exposure to Treasury yields and central-bank decisions.

This makes CME a picks-and-shovels exposure to monetary uncertainty. Greater disagreement can increase the need for price discovery and risk transfer, although volume, competition, regulation, and market conditions remain important risks. CME offers exposure to the infrastructure surrounding monetary policy rather than one bank’s balance-sheet risk.

Learn more about CME Group.

Financial Stability Is Not Free

The paper does not argue that central banks should ignore bank failures. Its important insight is that protection changes incentives.

A central bank that is highly responsive to financial losses may reduce immediate disruption but weaken its future credibility. Banks gain more influence over policy while receiving less reliable guidance, leaving them exposed to the surprises that communication was meant to prevent.

The researchers reach a provocative conclusion: society may benefit from a central banker who places less weight on financial stability than society itself does. Even banks could prefer that arrangement if clearer guidance becomes more valuable than policy influence.

For investors, the broader conclusion is simpler. Interest rates are not set in a vacuum. The structure of bank balance sheets, the concentration of the financial system, and the credibility of central-bank communication can all affect the path of policy. When financial stability and inflation control collide, the apparent rescue of the banking system may carry a less visible cost: weaker market discipline and a less trustworthy signal about where rates are going next.

References:

¹ Bonomi, G., & Uppal, A. (2026). When monetary policy for financial stability backfires: Communication with strategic banks. Journal of Economic Theory, 106253. https://doi.org/10.1016/j.jet.2026.106253