Measuring the K: Spending Flows and Wealth Gaps in 2026

The divergence in consumer spending is now stark. While spending growth for higher-income Americans remained stable over the last year, growth slowed for lower- and middle-income households, according to Bank of America Institute data. This split is widening, with the difference between middle- and higher-income spending the largest since early 2022. Financial stress is reaching a tipping point, with the National Foundation for Credit Counseling forecasting an all-time high in the first quarter of this year.

The wealth threshold for the top 10% has also risen sharply. The net worth required to be in that group grew from about $1.3 million to roughly $1.8 million over the last five years, largely due to rising stock and home values. In absolute terms, households already in the top 10% by net worth saw their wealth grow more than any other cohort during that period.

This flow of wealth is the core of the K-shape. The data shows a clear split: spending and net worth are expanding fastest for those already in the top tier, while the middle and lower-income groups face slowing growth and rising financial stress.

Market Impact: How the Divergence Moves Prices

The market's 2025 strength was a direct function of spending flows. The S&P 500 rose 17.9 percent including dividends last year, powered by AI investment and earnings growth that favored wealthier investors. This rally was a response to economic data showing strong consumer spending among upper-income households, which helped offset tariff headwinds.

That momentum has stalled in 2026. The market has pulled back 3.2 percent year-to-date, with the S&P 500 down 3.5% on price alone. This shift coincides with a clear slowdown in spending growth, a trend Goldman Sachs Research now expects to continue through the second half of the year.

The connection is straightforward. The market's recent climb was built on the spending power of the top tier. As that growth slows, the foundation for corporate earnings weakens. Goldman Sachs forecasts real consumer spending growth of just 1.0% in 2025, a significant deceleration that threatens the economic expansion underpinning equity valuations.

Catalysts and Risks: What to Watch in 2026

The core divergence in spending flows is the primary signal to monitor. The split between higher- and middle-income growth, now the widest since early 2022, is the engine of the K-shape. Any sustained widening or reversal in this gap will confirm or break the thesis. Watch for the next retail sales and spending reports to see if the slowdown for lower- and middle-income groups accelerates, which would pressure corporate earnings and consumer sentiment.

The Federal Reserve's policy stance is a major lever that could exacerbate or ease the split. The central bank is balancing inflation data against growth signals. Goldman Sachs forecasts only 1.0% real consumer spending growth in 2025, a deceleration that could force a more dovish pivot. However, if inflation proves sticky, tighter policy would hit lower-income households hardest, deepening the financial stress already at an all-time high for middle-income Americans.

Finally, political events pose a direct, disruptive risk to fragile spending flows. The recent government shutdown's market jitters are a reminder of this volatility. A new shutdown or a major trade policy shift could abruptly halt the spending momentum, particularly for those already stretched. The market's reaction to the last shutdown was a mixed signal, but the underlying consumer flows remain vulnerable.