Inflation: The Silent Tax on Your Portfolio

Written by the William Allan team · Published 2026-05-07

Most investors think about risk in terms of losing money. A stock drops. A company disappoints. A market correction wipes out a year of gains. These are visible, measurable, and painful in a way that registers immediately.

But there is another kind of risk that is far quieter, far slower, and in many ways far more dangerous over a lifetime of saving and investing. It does not show up as a red number on your brokerage statement. It does not make headlines when it strikes.

It is inflation. When prices rise faster than your money grows, purchasing power falls.

What Inflation Actually Does

Inflation is the gradual increase in the price of goods and services over time. At modest levels, it is a normal feature of a healthy economy. But for investors, even modest inflation compounds into a significant problem over long time horizons.

Consider this: at a 3% annual inflation rate, the purchasing power of a dollar is cut roughly in half over 24 years. In this illustration, a fixed dollar amount earning no interest would buy about half as much after 24 years, without losing a dollar on paper. Interest earned on savings would change the result, as would taxes and a different inflation rate.

This is what makes inflation such an insidious risk. It does not feel like a loss. The number in an account can stay the same or grow slowly while its real value, measured in what that money can actually purchase, falls. Whether it does depends on the return relative to inflation.

The figures above are hypothetical and for illustrative purposes only. Actual inflation rates vary and are not predictable.

The Problem With Cash on the Sidelines

There is always a tempting logic to holding cash. It feels safe. It is liquid. It does not go down in a market correction. And during periods of elevated interest rates, it can even generate a modest return.

Cash can lose purchasing power when its after-tax yield falls below inflation. The outcome depends on the instrument, its yield, taxes, and the period held. A non-interest-bearing balance, a savings account, and a Treasury bill need not produce the same result. When returns trail inflation over many years, the shortfall compounds.

This does not mean cash has no place in a portfolio. Liquidity matters. Having reserves for near-term needs and opportunities is sensible financial management. For longer-term goals, compare the after-tax yield with the purchasing power you need and the investment risk you can accept.

How Different Assets Have Responded to Inflation Historically

Not all assets respond to inflation the same way, and understanding those differences is useful context for long-term investors.

Fixed-rate bonds are exposed to inflation because fixed payments buy less as prices rise. Rising market interest rates also generally push existing fixed-rate bond prices lower. Cash has purchasing-power risk when its after-tax yield trails inflation. The SEC’s investor bulletin on bonds explains inflation and interest-rate risks.

Real assets such as real estate and commodities have often served as inflation hedges historically, though their performance has been inconsistent across different inflationary cycles and they carry their own distinct risks.

Long-run equity returns have exceeded inflation in many historical markets, but results vary by market and period. That broad history does not establish that a particular group of “quality” companies will reliably beat inflation. The UBS Global Investment Returns Yearbook 2025 provides historical context. For evaluating an individual business, one consideration is pricing power.

Historical asset class behavior is not predictive of future results. All asset classes carry risk. Individual securities and situations vary widely.

Pricing Power and Rising Costs

A business with pricing power may be able to raise the prices it charges customers when its own costs rise. That ability can help protect margins, but it does not guarantee that earnings or the stock’s return will outpace inflation.

Think about the kinds of businesses that tend to have this characteristic. Companies selling products or services that customers consider essential or difficult to replace. Brands with deep loyalty and limited competition. Businesses that operate in markets where switching costs are high. Those characteristics may give a business more room to respond to rising costs, depending on competition and customer demand.

By contrast, businesses with weak competitive positions, thin margins, and price-sensitive customers often struggle when inflation rises. Their costs go up and they cannot fully pass those increases along, which compresses profits.

This distinction matters enormously for investors thinking about inflation protection. Business economics matter alongside diversification, valuation, and the risks of owning stocks. Identifying promising characteristics does not remove the possibility of a loss.

The Compounding Effect Works Both Ways

Investors spend a great deal of time thinking about how compounding builds wealth. The same mathematical force works in reverse when inflation is eating into real returns year after year.

Real return is the investment return after accounting for inflation. It can be lower than the stated nominal return and can be negative even when an account balance rises. The question that matters for long-term purchasing power is not simply what a portfolio returned, but what remained after inflation, fees, and taxes.

Framing investment goals in real terms rather than nominal terms is a discipline that tends to produce clearer thinking and better long-term decisions.

A Long-Term Perspective

Inflation is a familiar planning risk. Accounting for it helps connect today’s savings decisions with the spending those savings will need to support.

The core insight is simple even if the execution requires care and judgment: holding cash involves tradeoffs among liquidity, yield, taxes, and purchasing power. A yield below inflation has a real cost. Taking more investment risk to pursue a higher return creates a different set of risks.

Durable competitive advantages and pricing power are useful considerations when evaluating a business. They may help a company respond to rising costs, but neither those traits nor stock ownership assures returns above inflation. For a long-term investor, the question is how those considerations fit within a diversified portfolio and a realistic spending plan.

Schedule a free first call to discuss the next step for your portfolio questions.

This commentary is for informational purposes only and is not investment, tax, or legal advice. All investing involves risk, including the possible loss of principal, and past performance does not guarantee future results.