What is CPI (inflation index) — definition and impact on investments 2026

What is CPI — definition

CPI (Consumer Price Index) is the Consumer Goods and Services Price Index, the most widely used inflation measure. CPI shows how prices of a basket of typical products and services purchased by households change.

In Poland, the equivalent is the inflation index published by GUS (Central Statistical Office).

CPI measures:

• Price growth rate of goods and services
• Purchasing power of money
• Real return of investments (after inflation)
• Price pressure in the economy

Current data (February 2026):

• CPI Poland: 3.8% y/y
• Core CPI: 4.2% y/y
• CPI USA: 2.9% y/y
• CPI Eurozone: 2.4% y/y

Quick Answer

CPI (Consumer Price Index) is the Consumer Goods and Services Price Index, the most widely used inflation measure, showing how prices of a basket of typical products and services purchased by households change. In Poland it is published monthly by GUS, which tracks around 750 products weighted by their share in spending. Core CPI strips out volatile food and energy to reveal underlying inflation. CPI shapes monetary policy against the NBP target of 2.5% ± 1% and determines the real return on savings and investments after inflation.

---

How CPI is calculated

"Inflation basket" methodology

Step 1: Selection of goods and services GUS selects about 750 products representative of Polish consumption:

• Food: Bread, milk, meat, vegetables
• Housing: Rent, electricity, gas
• Transport: Fuel, public transport tickets
• Clothing, health, recreation etc.

Step 2: Basket weights Each category has a weight corresponding to its share in spending:

Step 3: Price measurements GUS collects prices in 340 cities from:

• 26,000 sales points (stores, services)
• 6,000 apartments (rent)
• Online platforms (e-commerce)

Step 4: Calculations CPI = Σ (Category weight × Category price change)

Example calculations

Hypothetical price changes (year over year):

• Food: +8.2% (weight 20.8%)
• Housing: +4.1% (weight 21.2%)
• Transport: +12.5% (weight 13.1%)
• Other: +2.8% (weight 44.9%)

CPI = (0.208 × 8.2%) + (0.212 × 4.1%) + (0.131 × 12.5%) + (0.449 × 2.8%) CPI = 1.71% + 0.87% + 1.64% + 1.26% = 5.48%

CPI vs. Core CPI

Core CPI (core inflation)

Definition: CPI without food and energy (most volatile categories)

Why important:

• Food and energy subject to shocks (war, weather)
• Core CPI better reflects long-term trends
• Central banks often focus on core inflation

Poland comparison (February 2026):

• CPI headline: 3.8%
• Core CPI: 4.2%
• Difference: Core higher by 0.4 pp

Interpretation:

• High core = structural inflationary pressure (wages, rent)
• Low core = inflation mainly from food/energy (temporary)

Other inflation measures

CPI Trimmed Mean:

• Cuts 15% highest and 15% lowest price changes
• Eliminates statistical extremes
• Used by central banks for analysis

PPI (Producer Price Index):

• Prices at producer level
• Leading indicator for CPI (2-6 months ahead)
• PPI Poland: +5.2% (February 2026)

History of inflation in Poland

Economic transformation

Hyperinflation era (1989-1993):

• 1989: 251% (record)
• 1990: 585% (hyperinflation peak)
• Balcerowicz Plan gradually reduced inflation

Stabilization (1994-1999):

• Gradual decline to ~7-12%
• 1999: Introduction of inflation targeting (NBP)

Modern era (2000-2026)

Stable period (2000-2007):

• Inflation: 0.8-4.2%
• NBP target: 2.5% ± 1%
• EU membership, convergence

Financial crisis (2008-2009):

• 2008: 4.2% (commodity boom)
• 2009: 3.5% (global recession)

QE and low rates era (2010-2019):

• Average: 1.0% (below NBP target)
• 2015-2016: Deflation -0.6% and -0.9%
• Concerns about Japanese disease

Pandemic and war (2020-2026):

CPI and monetary policy

NBP inflation target

Target: 2.5% ± 1% (i.e., 1.5-3.5%)

Current situation (February 2026):

• CPI: 3.8% (above target by 0.3 pp)
• Core CPI: 4.2% (significantly above)
• Inflation expectations: 3.1% (2-year forward)

Interest rate reaction

Taylor rule (simplified): Rate = Natural + 1.5 × (Inflation - Target) + 0.5 × Output Gap

Example calculations (2026):

• Natural rate: 2.5%
• Inflation: 3.8%, Target: 2.5% → Gap = +1.3%
• Output gap: +0.5% (economy above potential)

Optimal rate = 2.5% + 1.5 × 1.3% + 0.5 × 0.5% = 4.7%

Actual NBP rate: 5.75% (more hawkish)

Forward guidance

NBP communication (February 2026):

• "Inflation remains elevated"
• "Rates will remain restrictive" until CPI returns to target
• First cut: Probably Q4 2026

Markets pricing:

• 6M: Rates unchanged (5.75%)
• 12M: 50 bp cut (to 5.25%)
• 24M: Normalization to 4.5%

CPI in different countries

International comparisons

Developed Markets (February 2026):

Emerging Markets:

Inflation convergence

Balassa-Samuelson effect:

• Catching-up countries (like Poland) have naturally higher inflation
• Productivity growth in tradables → wage growth → services inflation
• "Złoty up, inflation up" paradox

Long-term convergence:

• Poland → EU average: Still 5-10 years
• Target: 2.0-2.2% (like rest of EU)

CPI impact on asset classes

Bonds (most sensitive)

Mechanism:

• Higher inflation → Higher rates → Bond prices fall
• Real yield = Nominal yield - CPI

Historical example (2021-2022):

• CPI: 5.1% → 14.4%
• NBP rates: 0.1% → 6.75%
• 10Y bonds: -18% total return in 2022

Duration risk:

• Short-term bonds: Less sensitive
• Long-term bonds: Very sensitive
• TIPS/Indexed bonds: Protected from inflation

Stocks (mixed impact)

Positive impact (moderate inflation 2-4%):

• Pricing power — companies raise prices
• Real assets appreciation (real estate, inventory)
• Nominal revenues growth

Negative impact (high inflation >6%):

• Margin compression (costs rise faster)
• Higher discount rates → lower valuations
• Consumer demand destruction

Inflation-resistant sectors:

• Energy (natural hedge)
• Materials (commodities exposure)
• Real estate (inflation-linked rents)
• Banks (net interest margin expansion)

Inflation-sensitive sectors:

• Technology (high duration, high P/E)
• Consumer discretionary (margin pressure)
• Utilities (regulated rates, high debt)

Commodities (positive)

Inflation often = rising commodity prices

Gold vs. CPI (correlation 0.65):

• High inflation periods: Gold +15-25% p.a.
• Low inflation: Gold flat or negative
• Real yields negative → gold very attractive

Oil, agriculture, metals:

• Direct components of CPI basket
• Supply shocks often cause inflation

Real Estate

Positive long-term:

• Inflation hedge (rents adjust)
• Mortgage debt eroded by inflation
• Construction costs rise → higher values

Negative short-term:

• Higher mortgage rates → lower affordability
• 2022-2024: Housing prices -8% despite 14% inflation

Currencies

High inflation = Weak currency (usually)

• Purchasing power decline
• Real interest rates may stay negative
• Capital flight to hard currencies

PLN vs. EUR (inflation differential):

• Poland CPI > EU CPI → PLN weakness pressure
• But: Higher nominal rates may offset
• 2026: Relative performance depends on ECB vs. NBP

Investment strategies in different CPI regimes

Low Inflation Environment (CPI <2%)

Asset Allocation:

• Growth stocks (high duration benefit)
• Long-term bonds (capital appreciation)
• Technology outperformance
• Avoid: Commodities, gold

Risk:

• Deflation risk (Japan scenario)
• Zero Lower Bound monetary policy

Moderate Inflation (CPI 2-4%)

"Goldilocks scenario"

• Balanced portfolio 60/40 stocks/bonds
• Quality dividend stocks
• REITs for real asset exposure
• Slight commodity allocation (5-10%)

High Inflation (CPI >5%)

Defensive positioning:

• Inflation-protected bonds (TIPS)
• Commodity exposure (15-25%)
• Gold allocation (5-10%)
• Short duration bonds only

Sector rotation:

• Overweight: Energy, materials, banks
• Underweight: Tech, consumer discretionary

Hyperinflation (CPI >20%)

Capital preservation mode:

• Foreign currency assets
• Physical precious metals
• International diversification
• Bitcoin/crypto (controversial hedge)

Historical examples:

• Turkey 2021-2022: USD, Gold +100%+ in lira terms
• Argentina ongoing: USD assets essential

CPI Forecasting and leading indicators

Leading indicators CPI

1. Producer Price Index (PPI)

• Lead time: 2-6 months
• Current PPI: +5.2% → suggests CPI pressure continues

2. Wages growth

• Average wage: +12.1% y/y (February 2026)
• Services inflation correlates with wage growth

3. Money supply (M2)

• M2 growth: +8.4% (historical avg: 6%)
• Milton Friedman: "Inflation is always monetary phenomenon"

4. Commodity prices

• Oil: $82/barrel (+15% y/y)
• Food commodities: +8% average
• Direct CPI components

5. Exchange rate

• EUR/PLN: 4.42 (relatively stable)
• PLN weakness → imported inflation
• PLN strength → disinflationary

CPI forecasting models

NBP projections (March 2026):

• 2026 average: 3.9%
• 2027: 2.8%
• 2028: 2.5% (back to target)

Market-based measures:

• 5Y5Y inflation swaps: 2.7%
• 10Y breakevens: 2.9%
• Anchored but elevated vs. target

Risks to forecasts:

Upside:

• Wage-price spiral establishment
• Energy price shocks (geopolitical)
• PLN weakness (Fed cuts → EM outflows)

Downside:

• EU recession spillover
• Commodity price crash
• Demand destruction from high rates

Freenance and CPI hedging

Inflation-protected portfolio in Freenance

Smart Asset Allocation:

• Automatic rebalancing based on CPI data
• TIPS/Inflation-linked bond allocation
• Commodity ETFs in high inflation periods
• Real estate exposure (REITs)

Example allocation (CPI > 3.5%):

• 40% Equities (inflation-resistant sectors)
• 20% Inflation-protected bonds
• 15% Commodities/Gold
• 15% International diversification
• 10% Cash (high-yield savings)

Dynamic hedging strategies

CPI-triggered rebalancing:

• CPI > 4%: Increase commodities to 20%
• CPI < 2%: Increase growth stocks to 70%
• Volatility > 30%: Increase cash buffer

Income optimization:

• High CPI periods: Focus on dividend aristocrats
• Low CPI: Growth compounders
• Real yield tracking: Maintain positive real returns

Open Freenance account and protect your portfolio from inflation with automatic CPI-hedging strategies!

Future of CPI measurement

Digital economy challenges

Measurement issues:

• Free digital services (Google, Facebook)
• Quality improvements (hedonic adjustments)
• Sharing economy (Uber, Airbnb)
• E-commerce substitution bias

BLS/GUS improvements:

• Real-time data collection
• Online price tracking
• Scanner data from retailers
• Machine learning algorithms

Central Bank Digital Currencies (CBDCs)

Potential CPI impact:

• Real-time consumption data
• More accurate measurements
• Policy transmission improvements
• Privacy vs. accuracy tradeoffs

Summary

CPI is the most important inflation indicator that fundamentally impacts all investments:

✓ Measures consumer price growth rate ✓ Drives monetary policy decisions ✓ Key input for asset allocation ✓ Different assets react differently to CPI changes ✓ Long-term: Protect purchasing power

For investors: Monitor CPI releases and adjust portfolio to inflation regime. High CPI = real assets + commodities, Low CPI = growth stocks + long bonds.

Current context: CPI above NBP target, but declining trend. Expect gradual normalization to 2.5% in 2027-2028.

Use Freenance for building inflation-resistant portfolio and real-time CPI monitoring!

Related Articles

• Jak oszczędzać na paliwie w 2026 — 15 sprawdzonych sposobów
• Lokata vs konto oszczędnościowe 2026 — co wybrać? Porównanie oprocentowania

FAQ

What does CPI actually measure?

CPI (Consumer Price Index) tracks the average change over time in the prices households pay for a representative basket of goods and services. In Poland it is published monthly by GUS and is the headline gauge that NBP and the public use to talk about inflation. A higher CPI means the same złoty buys less than a year ago.

Why do economists also look at Core CPI?

Core CPI strips out food and energy prices because those categories are highly volatile and often driven by shocks like weather or oil markets. By removing them, Core CPI gives a cleaner read on underlying, more persistent inflation in services and other goods. Central bankers tend to weight Core CPI heavily when judging whether inflation pressure is structural.

How does CPI affect interest rates set by NBP?

NBP has an inflation target of 2.5% with a tolerance band of plus or minus one percentage point. When CPI runs persistently above target, the Monetary Policy Council typically keeps rates restrictive to cool demand and inflation expectations. When CPI heads back toward target, the Council can consider cutting rates, although the timing depends on the full forecast picture.

How does CPI affect my real return on savings and bonds?

Real return is roughly the nominal interest rate minus CPI. If a deposit pays 5% and CPI is 4%, the real return is only about 1% before tax. When CPI exceeds the rate you earn, your purchasing power shrinks even if your balance grows, which is why comparing yields to current inflation matters for savers and bondholders alike.

Is CPI the same thing as my personal cost of living?

Not exactly. CPI uses a national average basket with fixed weights, while your spending mix can look very different depending on whether you rent, own, drive a lot or have children. Personal inflation can be meaningfully higher or lower than headline CPI, so using your own budget data alongside CPI gives a more realistic picture of how rising prices hit you.