The Core PCE Price Index is a key inflation indicator that the Federal Reserve closely watches. A steady figure suggests that inflation is not accelerating, which can lead to stable interest rates and potentially positive market sentiment. However, since the data met expectations and showed no change from the previous month, the immediate impact on SPY, an ETF that tracks the S&P 500 and is sensitive to economic indicators, is likely to be neutral. Investors had likely already priced in these expectations.