Recently, I’ve been studying the pattern behind the timing of the U.S. CPI releases, and I’ve found that this data’s impact on global asset prices should not be underestimated.

First, a basic piece of common knowledge: the U.S. CPI is usually released on the first business day of each month—or on the closest business day. In Taiwan time, it’s roughly between 20:30 and 21:30. The exact timing may be adjusted depending on daylight saving time and standard time. This data is important because it is released before the PCE data published, which the Federal Reserve uses as a basis for its decisions. As a result, the market is especially sensitive to CPI, and it often triggers relatively large asset price volatility.

I’ve noticed that many people tend to confuse the difference between CPI and core CPI. In fact, core CPI excludes the two most volatile categories—food and energy—so it’s easier to see the true price trend of other consumer goods. And the biggest difference between PCE and CPI lies in their calculation methods: PCE uses chain-weighted indexing, which more effectively reflects consumers’ substitution effects and serves as a kind of “peak shaving and valley filling” mechanism for inflation volatility.

I believe investors should focus on two indicators: first, the U.S. CPI year-over-year growth rate, because it’s released earliest and the market reacts most sharply to it; second, the U.S. PCE year-over-year growth rate, because this is the Federal Reserve’s actual decision-making basis. Typically, the direction of changes in these two indicators is consistent, and their magnitudes are also close.

From the composition of CPI, housing-related spending has the largest share (30-40%), followed by food and beverages (13-15%). These two are the key areas to analyze. Other categories include healthcare and insurance, energy, transportation, education, and communications.

Looking back at history, U.S. CPI has gone through four major cycles of sharp rises and falls. The savings and loan crisis in the 1990s, the dot-com bubble in 2000, the subprime mortgage crisis in 2008, and the pandemic shock in 2020—each time CPI fell, it corresponded to an economic crisis. Especially in 2020, the impact of global logistics conditions on inflation was far greater than many people expected. Later, the Red Sea crisis once again disrupted regional logistics, and freight rates on Asia-Europe routes rose by more than two times in a short period.

When it comes to the timing and trend of U.S. CPI releases, I’ve observed that there are mainly two factors with the biggest impact. The first is the strength or weakness of the U.S. economy itself. According to International Monetary Fund forecasts, the U.S. economy’s growth rate ranks among the top among major countries globally, which means inflation is unlikely to fall to very low levels. The second is commodity prices—especially crude oil—because changes in crude oil inventories and prices directly affect how the energy component performs in CPI.

Taken together, these factors—logistics costs, geopolitical conditions, and energy supply—ultimately show up in consumer prices. Therefore, if you want to predict the CPI trend, you can’t rely on statistical data alone; you also need to track changes in these underlying fundamentals. For investors who care about the timing of the U.S. CPI release, the key is to understand these driving factors, not just to follow the release date.