Trumpflation Is Evolving, and There's a New Twist That Threatens to Sink Stocks

For the better part of the last four years, the stock market has been unstoppable. The artificial intelligence (AI) infrastructure build-out has helped propel the Dow Jones Industrial Average (DJINDICES:^DJI), S&P 500 (SNPINDEX:^GSPC), and Nasdaq Composite (NASDAQINDEX:^IXIC) to several record highs this year.

But these gains may prove fleeting, courtesy of Trumpflation -- inflation specifically driven by President Donald Trump's policies -- and a new twist identified by Federal Reserve policymakers that throws a serious monkey wrench into their rate-hiking cycle.

Trumpflation is evolving -- and that's a big problem

Inflation isn't inherently bad. Modest inflation is expected if the U.S. economy is growing and businesses possess some degree of pricing power over their goods and services. Over the long run, the Federal Reserve targets a 2% inflation rate.

However, two of President Trump's policies lifted the annualized inflation rate to a three-year high of 4.2% in May. It's this persistently elevated inflation that prompted the Federal Open Market Committee (FOMC) to raise interest rates by a quarter-point on Sept. 16.

The first culprit is Trump's tariff and trade policy. According to a new report ("How Fast Do Tariffs Pass Through into Consumer Prices") by three New York Federal Reserve economists writing for Liberty Street Economics, the president's tariffs increased goods price inflation by 2.9 percentage points by February 2026.

New from the New York Fed: "By February 2026, tariffs had contributed 2.9 pp to goods price inflation, and without them goods prices would have fallen slightly." About one quarter of every point in higher tariff rates shows up in consumer prices within one year. • A 10% across-the-board tariff yields a 2.6% rise in consumer goods prices after one year. • About two thirds of the increase comes from pricier imports, which get passed through quickly. • Another third comes from U.S. made goods, as producers face higher input costs and less import competition. This takes longer, about 6-12 months, to filter through.

— Nick Timiraos (@NickTimiraos) October 6, 2026

The Trump-led Iran war is also adversely impacting consumer prices. The ongoing closure of the Strait of Hormuz has disrupted the daily flow of approximately 20 million barrels of crude oil, sending diesel prices to record highs.

But Trumpflation is also evolving -- and that's a big problem.

Core inflation data suggest that the Iran war is no longer just a story of energy supply disruption. Businesses are being forced to alter their modes of transportation, shift shipping routes, and change suppliers, resulting in higher expenses that are passed on to consumers. The more Trumpflation evolves and becomes entrenched in the U.S. economy, the more likely the FOMC will need to get aggressive with its rate-hiking cycle.

A new inflation twist bodes poorly for the stock market

But it's not just Trumpflation that the Fed and investors have to worry about. In June, FOMC policymakers identified a new source of inflation that'll be incredibly difficult to tackle: the AI infrastructure build-out.

For the stock market, the evolution of artificial intelligence has been a godsend. The insatiable demand for graphics processing units (GPUs) and high-bandwidth memory (HBM), among other products, has afforded these businesses exceptional pricing power.

The AI boom is transforming one of the biggest deflationary forces into a key source of US inflation: Import prices for computer and electronic products surged +7.4% in the first 6 months of 2026, to 77.1 points, the highest since January 2016. This also marks a +8.0% YoY jump, the largest annual increase on record. This represents a historic reversal from a downtrend which persisted for over two decades. Between 2006 and 2019, computer and electronic product import prices fell -30%, as improving technology and manufacturing efficiency consistently pushed costs lower. Now, the AI investment boom is straining manufacturing capacity for semiconductors, servers, and electronic components, as companies race to build out AI infrastructure regardless of cost. The AI revolution has flipped technology from a long-term source of deflation into a major driver of inflation.

— The Kobeissi Letter (@KobeissiLetter) July 21, 2026

Unfortunately, otherworldly pricing power comes at a potentially steep cost. Between persistent GPU and HBM supply shortages and strong pricing power, higher costs for processing chips and memory have worked their way down to the consumer level. Several tech-driven devices, such as laptops and smartphones, now cost more because of the AI infrastructure build-out.

This inflation twist puts the Federal Reserve in a bind. If FOMC policymakers raise interest rates several times to deliver price stability, they risk upending the AI-driven bull market. The AI data center build-out wouldn't be possible without debt-driven financing. If borrowing costs meaningfully rise in the coming quarters, it could spell the end of the AI boom and the second-priciest stock market in history.

Sean Williams has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.