Why Interest Rates Must Increase During Periods of High Inflation
Introduction
Persistent inflation poses significant challenges for households, businesses and policymakers because it reduces purchasing power, distorts economic decision-making and increases uncertainty about future prices. While moderate inflation is generally associated with economic growth, prolonged periods of elevated inflation can undermine consumer confidence, discourage productive investment and weaken the effectiveness of financial markets (RBA 2026; Bernanke, Antonovics & Frank 2023).
In Australia, the Reserve Bank of Australia (RBA) is responsible for maintaining price stability through monetary policy. However, the rationale for increasing interest rates during inflationary periods extends beyond simply meeting an inflation target. Inflation influences bond markets, investor expectations, exchange rates and the overall cost of capital throughout the economy. When inflation becomes elevated, higher interest rates are often required not only to restrain demand but also to preserve confidence in financial markets and maintain the value of the currency (RBA 2026; Mishkin 2022). Understanding these broader relationships helps explain why central banks frequently raise interest rates during periods of sustained inflation.
The Reserve Bank’s Inflation Mandate
The RBA conducts monetary policy with the objective of maintaining consumer price inflation between 2 and 3 per cent over time (RBA 2026). This target reflects the view that low and stable inflation supports sustainable economic growth, encourages investment and promotes long-term prosperity (RBA 2026).
When inflation rises significantly above the target range, the purchasing power of money declines. As prices increase faster than incomes, households experience a reduction in real spending capacity and living standards may deteriorate (Chalmers & Hewson 2026). High inflation can also distort business decision-making because firms face greater uncertainty regarding future costs, consumer demand and investment returns (RBA 2026; Mishkin 2022).
The primary tool available to the central bank is the cash rate. By increasing policy interest rates, borrowing becomes more expensive for households and businesses. Higher borrowing costs tend to reduce consumption and investment expenditure, slowing aggregate demand and alleviating pressure on prices (Mishkin 2022; RBA 2026). Although the effects of monetary policy occur with a lag, interest rate increases remain one of the most effective mechanisms for reducing inflationary pressure.
Inflation Expectations and Policy Credibility
A particularly important justification for raising interest rates during periods of high inflation is the need to manage inflation expectations. Modern macroeconomic theory recognises that inflation is influenced not only by current economic conditions but also by expectations regarding future inflation (IMF 2023).
When consumers and businesses believe prices will continue rising rapidly, they alter their behaviour accordingly. Employees may seek larger wage increases to protect real incomes, while businesses may increase prices in anticipation of future cost increases. These responses can reinforce inflation and make it more persistent over time (IMF 2023; Bernanke, Antonovics & Frank 2023).
For this reason, central bank credibility is crucial. If households, businesses and financial markets remain confident that policymakers will return inflation to target, long-term inflation expectations are more likely to remain anchored. However, if policymakers are perceived as unwilling to respond adequately to inflation, expectations may become detached from the target range, increasing the likelihood of persistent inflation and requiring more aggressive policy interventions later (IMF 2023).
Interest rate increases therefore serve both a practical and symbolic role. They reduce demand directly while simultaneously signalling the central bank’s commitment to restoring price stability. Maintaining that credibility is essential for ensuring inflation remains under control over the long term (RBA 2026; IMF 2023).
Inflation, Bond Markets and the Fisher Effect
The relationship between inflation and interest rates is not determined solely by central bank policy. Financial markets also influence interest rates through the pricing of government bonds and other debt securities.
According to the Fisher Effect, nominal interest rates reflect both the real return required by investors and expectations regarding future inflation (Mishkin 2022). When inflation expectations rise, investors generally demand higher nominal returns to protect the real purchasing power of future income streams.
This relationship is particularly evident in bond markets. Government bonds provide investors with fixed future payments; therefore, higher inflation reduces the real value of those payments. Abbas and Togo (2025) explain that investors require additional compensation for expected inflation, causing bond yields to rise when inflation expectations increase.
As inflation becomes elevated or appears likely to remain elevated, investors typically sell existing bonds and demand higher yields on newly issued securities. Consequently, bond prices fall and yields increase. These market responses occur because investors seek protection against inflation risk rather than because central banks directly control long-term bond yields (Abbas & Togo 2025).
Bond markets therefore function as an important discipline on monetary policy. If investors doubt that a central bank will successfully control inflation, inflation risk premiums may increase and long-term yields may rise substantially (Shapiro & Lefort 2026). In contrast, credible anti-inflation policies help anchor expectations and support more stable bond markets.
From Bond Yields to Lending Rates
The effects of rising bond yields do not remain confined to government debt markets. Government securities form the foundation of modern financial systems and influence interest rates across a wide range of lending products (Mishkin 2022).
Commercial banks obtain funding from several sources, including deposits, wholesale money markets and bond issuance. When government bond yields increase, the cost of wholesale funding generally rises as well. Financial institutions subsequently pass these higher funding costs on to consumers and businesses through increased mortgage rates, personal loan rates and commercial lending rates (Abbas & Togo 2025; Mishkin 2022).
Corporate borrowers experience similar effects. Businesses issuing debt must compete with government securities for investor capital. As government bond yields increase, companies generally need to offer higher returns to attract investors, increasing the cost of borrowing throughout the economy (Bernanke, Antonovics & Frank 2023).
This transmission mechanism explains why inflation can generate higher borrowing costs even if a central bank has not yet adjusted its policy rate. However, if policymakers fail to respond appropriately, rising market interest rates may occur alongside deteriorating inflation expectations, creating additional instability. Raising policy rates can therefore reinforce market signals and help restore confidence in the monetary policy framework.
Exchange Rates and Imported Inflation
Inflation also influences exchange rates through capital flows and investor confidence. International investors allocate capital toward countries offering attractive risk-adjusted returns and credible economic management (Mishkin 2022).
If inflation rises while domestic interest rates remain relatively low, investors may shift capital to other markets offering superior real returns. Reduced capital inflows can weaken the domestic currency, making imports more expensive and intensifying inflationary pressure (Mishkin 2022).
For a country such as Australia, which imports substantial quantities of manufactured goods, machinery, vehicles and fuel products, exchange rate depreciation can lead to higher domestic prices for imported goods and services (Mishkin 2022; RBA 2026). This phenomenon is commonly described as imported inflation.
Higher interest rates can help mitigate this risk by supporting the exchange rate and maintaining investor confidence. By increasing the attractiveness of Australian financial assets, tighter monetary policy may encourage capital inflows and reduce some of the inflationary pressure associated with a weaker currency (Mishkin 2022; RBA 2026).
Consequently, interest rate increases support inflation control not only through reduced domestic demand but also through exchange-rate channels.
Financial Stability Considerations
A further justification for higher interest rates during inflationary periods is the preservation of financial stability. Persistent inflation creates uncertainty regarding future prices, investment returns and borrowing costs. Such uncertainty can discourage long-term planning and increase volatility across financial markets (Bernanke, Antonovics & Frank 2023).
Elevated inflation may also contribute to rising government borrowing costs as investors demand greater compensation for inflation risk. Dabla-Norris and Valdés (2026) argue that persistent inflation and rising sovereign yields can create additional fiscal pressures, particularly in economies with significant debt burdens.
Higher inflation can therefore affect not only consumers and businesses but also governments, whose financing costs may increase substantially. If inflation remains unchecked, financial market volatility and borrowing costs can rise simultaneously, creating broader economic risks (Dabla-Norris & Valdés 2026).
Although tighter monetary policy may slow economic growth in the short term, the long-term costs of allowing inflation to become entrenched are often considerably greater. History demonstrates that delayed responses to inflation frequently require more aggressive policy tightening later and may result in deeper economic downturns (IMF 2023).
Counterarguments and Limitations
Despite the strong case for higher interest rates during inflationary periods, monetary policy is not a perfect solution. Some inflationary episodes originate from supply-side disruptions such as geopolitical conflict, energy price shocks or supply-chain constraints. In such situations, higher interest rates cannot directly increase production or resolve shortages (Bernanke, Antonovics & Frank 2023).
Nevertheless, central banks remain concerned with preventing temporary price shocks from becoming embedded in expectations and wage-setting behaviour. Even where inflation initially arises from supply-side factors, elevated inflation can spread through the broader economy if expectations become unanchored (IMF 2023).
Accordingly, policymakers often conclude that some degree of monetary tightening remains necessary to prevent inflation from becoming persistent, even when its original causes lie outside domestic demand conditions.
Conclusion
Interest rates must increase during periods of high inflation for reasons that extend well beyond the Reserve Bank of Australia’s inflation-targeting mandate. Elevated inflation reduces purchasing power, distorts household and business decision-making, undermines the real value of savings and wages, and increases uncertainty throughout the economy. If left unchecked, inflation can become embedded in expectations, making future price increases more persistent and significantly more difficult to reverse.
The need for higher interest rates is reinforced by financial markets. As inflation expectations rise, investors demand higher bond yields to compensate for the declining purchasing power of future cash flows. These higher yields flow through to wholesale funding costs, mortgage rates, business lending rates and government borrowing costs, effectively tightening financial conditions across the economy. At the same time, inadequate policy responses can weaken investor confidence, place downward pressure on the exchange rate and contribute to additional imported inflation.
By increasing interest rates, central banks help moderate aggregate demand, anchor inflation expectations, support currency stability and maintain confidence in both monetary policy and financial markets. Although tighter monetary policy may impose short-term costs through slower economic growth and higher borrowing expenses, the long-term economic costs of allowing inflation to remain elevated are typically far greater. Consequently, interest rate increases remain an essential tool for preserving price stability, supporting sustainable economic growth and protecting the long-run prosperity of the economy.
References
Abbas, SMA & Togo, E 2025, Bonds and yields, International Monetary Fund, Washington, DC, viewed 3 November 2026, <https:
Bernanke, B, Antonovics, K & Frank, R 2023, Principles of economics, 9th edn, McGraw-Hill Education, New York.
Chalmers, S & Hewson, G 2026, Why is inflation so high and why is the RBA raising interest rates to bring it down?, ABC News, viewed 3 November 2026, <https:
Dabla-Norris, E & Valdés, R 2026, Rising sovereign yields raise the fiscal stakes, International Monetary Fund, viewed 3 November 2026, <https:
International Monetary Fund (IMF) 2023, World Economic Outlook October 2023: Managing expectations – inflation and monetary policy, International Monetary Fund, Washington, DC, viewed 3 November 2026, <https:
Mishkin, FS 2022, The economics of money, banking and financial markets, 13th edn, Pearson, Harlow.
Reserve Bank of Australia (RBA) 2026, Australia’s inflation target, Reserve Bank of Australia, Sydney, viewed 3 November 2026, <https:
Reserve Bank of Australia (RBA) 2026, Monetary policy, Reserve Bank of Australia, Sydney, viewed 3 November 2026, <https:
Shapiro, J & Lefort, C 2026, The bond market offers cheap bets the RBA will fail on inflation, Australian Financial Review, viewed 3 November 2026, <https: