Do Aggregate State Tax Revenues Lead the Stock Market

A subscriber asked whether aggregate U.S. state tax revenues, as an indicator of economic activity, lead the U.S. stock market. To investigate, we compare behaviors of total quarterly state tax collections and SPDR S&P 500 ETF Trust (SPY). Because these series are not stationary (generally increasing rather than mean reverting), we relate changes in them. Because the state tax revenues exhibit strong seasonality, we focus on a 4-month simple moving average (SMA4) of state tax revenues. Because the SMA4 series involves substantially overlapping measurements that can distort statistics, we also look at annual measurements. Using quarterly state tax collections data and quarterly dividend-adjusted prices for SPY as available from the first quarter of 1994 (limited by tax collections data) through the second quarter of 2023, we find that: (more…)