Will the U.S. CPI next week trigger an interest rate hike in September? Bank of America and Citibank provide two opposing scenarios.

The US August CPI data, set to be released next Friday, will directly determine whether the Federal Reserve can restart interest rate hikes in this month's meeting. Major institutions on Wall Street have significant disagreements over how to interpret this reportBank of America believes the data will be strong enough to support a rate hike in September, while Citigroup expects core inflation to cool further, making it more likely that the Fed will stay put. According to Wind Information, Bank of America predicts that the core CPI will rise by 0.22% month-on-month in August, corresponding to a core PCE increase of about 0.24%, and the annual rate will rise to 3.4%. They believe this level is sufficient to convince Fed Chair Powell that inflation has not been fully controlled, thereby supporting another rate hike. Bank of America sees August CPI as "a crucial battle" for the September rate hike. In contrast, Citigroup predicts that the core CPI will only increase by 0.184% month-on-month, leading to an annual rate drop to 2.3%if realized, this would be the lowest annual reading for core CPI since it exceeded 2% in April 2021, likely prompting the majority of officials to opt to maintain interest rates. Meanwhile, some analysts warn that if the CPI data exceeds expectations with a hotter outcome, coupled with core PCE inflation already at a high of 3.9% and robust employment data for August, the Fed may be forced to take a more aggressive tightening path, raising rates above 5% and actively inverting the yield curve, which would put significant downward pressure on US equities. Key Threshold: Waller's Vote Affects the Overall Situation The decision on rate hikes in the September meeting will largely depend on the internal voting dynamics of the Federal Reserve. Analysts suggest that the hawkish and dovish factions within the Fed are evenly matched, and Governor Waller is seen as a pivotal swing vote. Waller previously told Reuters, "If inflation continues to make progress towards the 2% target, I would be willing to support keeping the current policy interest rate unchanged," and specifically pointed out that the August inflation data would be a critical basis for his decision. Bank of America's report indicated that Powell signaled a clear hawkish stance at the Jackson Hole meeting, seemingly lowering the threshold for another rate hike; meanwhile, Williams and Waller's positions are relatively dovish. According to Bank of Americas analysis, Waller's implicit threshold is that he will only support a rate hike if the August core PCE rises over 0.30%. They predict core PCE to be about 0.24%, below this threshold, but believe that if Powell supports a hike and the data generally meets expectations, there could still be a sufficient majority within the committee to support another interest rate increase. Citigroup believes that, following Wallers comments this week, the market's threshold for identifying "overheating" inflation has shifted upwardsany data that rounds to a still 0.2% month-on-month increase may be seen as sufficiently moderate for most officials to support a pause in rate hikes. Core Disagreement: CPI and PCE Tell Different Stories The fundamental reason for the divergence in predictions lies in the structural differences between the two key inflation indicators, CPI and PCE, which are currently telling distinctly different inflation stories. Analysis shows that housing accounts for about a third of the CPI basket, whereas PCE has a significantly lower weight for housing. Over the past year, the cooling of housing inflation has been the primary driver of the decline in core CPI and is a core reason for the widening gap between CPI and PCE. Meanwhile, PCE places a higher weight on healthcare and includes expenditures from Medicare, Medicaid, and employer coverage, while CPI mainly measures out-of-pocket expenses. As a result, rising healthcare costs are pushing core PCE higher, especially super core PCE. The Cleveland Fed's inflation forecasting model indicates that core CPI is expected to further drop to 2.3% in September, approaching the Feds 2% target, while core PCE is expected to rise to about 3.5% during the same period, showing a clear divergence in trends. Fed Chair Powell has confirmed in his Jackson Hole speech that PCE inflation is the Fed's preferred policy reference indicator, with particular attention to super core PCEwhich excludes energy and housing from PCE services inflation. This metric has risen to 3.9% and is still trending upwards, reflecting persistent wage-driven inflationary pressures in the service sector. Energy and Employment: Two Cards Bolstering the Hawks' Confidence Regardless of the final data, the August employment report has already provided strong support for the hawks. In August, non-farm payrolls added 162,000 jobs, far exceeding the market expectation of 55,000, with annualized wage growth reaching 3.1%. This data was released after Waller made his statements, suggesting that the Fed will need to re-evaluate the wage-inflation dynamics. On the energy front, both Bank of America and Citigroup expect energy prices to rebound in August after several months of decline, pushing the overall month-on-month CPI increase to around 0.34% to 0.37%, with the annual rate rising further from July's level of about 3.4%. Analysts point out that ongoing tensions in the Middle East, with the Strait of Hormuz not returning to normal navigation, and declining global oil inventories could lead to a sharp rise in energy prices. This would not only push overall inflation higher but could also transmit through a wage-price spiral to core inflation, further intensifying tightening pressure on the Fed. Interest Rate Hike Expectations Rekindled, Stock Market Under Pressure For investors, the market implications of this CPI report cannot be overlooked. The current Shiller PE ratio of the S&P 500 has exceeded 42, placing it in bubble valuation territory, which historically corresponds to later stages of the economic cycle and has been further amplified by the AI capital expenditure boom. Analysts believe that if the Fed is forced to adopt a more aggressive tightening path, raising rates above 5% and actively inverting the yield curve, US stocks will face significant risks of PE compression. Bank of America argues that even if the composition of August inflation data does not trigger significant alarm, it is unlikely to provide the committee with sufficient reasons to delay a rate hike. The data release on September 11 will be a crucial test for the Fed's policy direction in the near term. Following CPI, the August PCE data will be released at the end of September, two weeks after the Fed's September interest rate decision. Citigroup points out that the uncertainty surrounding the August PCE data is higher than usualthis is due to methodological adjustments the Fed has made to some key components, which means that the conventional mapping of CPI and PPI data to PCE has become less clear this month, while the historical data for PCE over the past five years will also face revisions, which are expected to lower the core PCE annual rate by over 30 basis points to around 3.0%. This technical factor adds complexity to the markets interpretation of final PCE readings.