Inflation Is Not Bad for Stocks — Mispriced Inflation Is

For decades, we've been told that inflation is the enemy of equity returns. Rising prices erode corporate margins, force the Fed to hike rates, and compress valuations. The narrative is so ingrained that traders sell on hot CPI prints almost reflexively. But the data tells a different story.

What actually matters isn't whether inflation is high or low. What matters is whether inflation is higher or lower than expected. The surprise, not the level, drives returns.

This distinction has profound implications for portfolio construction. It means that the conventional approach—reducing equity exposure when inflation rises—is often exactly wrong. A period of elevated but stable inflation can be perfectly fine for stocks. It's the unexpected surge, the surprise print that markets haven't priced in, that causes the damage.

The mechanism is straightforward. Markets are discounting machines. When inflation runs at 5% for months in a row, that 5% is already embedded in bond yields, equity valuations, and sector positioning. The market has adjusted. But when inflation jumps from 3% to 5% unexpectedly, everything reprices at once—and repricing is painful.

The surprise framework

To measure inflation surprise, we compare actual CPI to market expectations using the 5-year breakeven inflation rate. When CPI comes in more than 2 percentage points above expectations, we call that a "large upside surprise." When it's within half a percentage point either way, inflation is "in line" with expectations.

The results are striking. Over the past twenty years, periods when inflation was correctly anticipated produced average 6-month S&P 500 returns of +9.45%. Large upside surprises? Negative 3.72%. That's a 13-percentage-point gap based solely on whether inflation was expected or not.

The chart reveals three distinct periods. From 2019 through early 2021, inflation consistently surprised to the downside—actual readings came in below expectations. This was the era of "transitory" deflation fears. Stocks soared.

From mid-2021 through late 2022, inflation surprised violently to the upside. Actual CPI exceeded expectations by 3-6 percentage points. This wasn't just high inflation—it was unexpectedly high inflation. Markets suffered accordingly.

Since early 2023, the surprise has narrowed. Inflation remains above the Fed's target, but it's no longer shocking anyone. Markets have adapted. Stocks have rallied.

Why level matters less than you think

Consider two scenarios. In the first, inflation runs at 5% for an entire year, but markets expect 5%. In the second, inflation averages 3%, but markets consistently expected 2%.

Conventional wisdom says the first scenario is worse—higher inflation, tighter policy, compressed multiples. But the data disagrees. Correctly anticipated 5% inflation produces better equity returns than persistently underestimated 3% inflation.

The pattern is clear: moderate inflation with upside surprise (+5.62%) beats high inflation with upside surprise (-3.58%) by 9 percentage points. But the biggest gap is within each level. For moderate inflation, "in line" returns (+9.12%) beat upside surprises (+5.62%) by 3.5 points.

The small sample for "high inflation, in line" (just 2 months) reflects the reality that high inflation rarely stays stable long enough for expectations to catch up. By the time markets adjust, inflation is usually falling. This itself is informative—sustained high inflation without surprises almost never happens.

The pricing power premium

If surprise matters more than level, then the stocks that perform best during inflationary periods should be those that can pass through unexpected cost increases without losing customers. This is pricing power—the ability to raise prices without destroying demand.

Companies with high gross margins have demonstrated pricing power. They've proven that customers will pay premium prices. When unexpected inflation hits, these companies can adjust faster than competitors with thinner margins.

Consider the contrast between LLY (83% gross margin) and a grocery retailer like KR (22% gross margin). When costs rise unexpectedly, Lilly can maintain absolute margins while Kroger faces an immediate squeeze. Both may eventually pass through costs, but the high-margin business has time and flexibility that the low-margin business lacks.

High pricing power stocks: Inflation beneficiaries

These companies have demonstrated the ability to maintain margins through cost increases. Their high gross margins provide a cushion when input costs rise unexpectedly.

Low margin stocks: Inflation vulnerable

These companies face margin pressure when costs rise unexpectedly. Thin margins leave little room for error, and passing through costs risks losing price-sensitive customers.

Note that recent returns don't perfectly align with margin profiles—RTX (+58%) and CMI (+61%) have outperformed despite thin margins. This reflects the current "in line" inflation regime where surprise is minimal. The margin distinction becomes critical when surprises occur.

Current positioning

Where does this leave us today? Current CPI runs at 2.65%, with 5-year breakevens around 2.31%. That's a modest upside surprise of 34 basis points—well within the "in line" zone that historically produces strong equity returns.

This is constructive. Markets aren't being blindsided by inflation. They've had time to adjust expectations, reprice bonds, and reposition portfolios. The repricing pain of 2022 reflected unexpected inflation; the gains of 2023-2025 reflect inflation that's elevated but anticipated.

The risk isn't current inflation levels. The risk is a new surprise—either an unexpected surge from supply shocks or an unexpected collapse that signals demand weakness. Both would require repricing; both would hurt returns.

What to watch

Three signals can provide early warning of inflation surprise shifts:

Breakeven rates: If 5-year breakevens rise sharply while actual inflation stays stable, it suggests markets expect acceleration. This narrows the potential upside surprise—good for risk-taking. If breakevens fall while inflation stays elevated, surprise risk increases.

CPI components: Headline CPI can mask divergences. Watch shelter (44% of index) and energy (7%) separately. Energy surprises tend to be larger and more volatile; shelter surprises are slower but stickier.

Wage growth: Wages are the largest cost for most businesses and the primary driver of services inflation. If wage growth reaccelerates unexpectedly, it signals potential inflation surprises ahead.