2 Stocks Are Carrying the Entire Earnings Boom: Nvidia and Micron Account for 34% of S&P 500 Profit Growth

2 Stocks Are Carrying the Entire Earnings Boom

The short answer: S&P 500 third-quarter earnings are expected to jump about 30% from a year ago, but Nvidia and Micron alone account for 34% of that growth, according to FactSet estimates and a Dow Jones Market Data analysis reported by The Wall Street Journal on October 24, 2026. Widen the lens to just 10 companies, and they account for roughly two-thirds of all the profit growth in the index.

That is the story blowing up this weekend: the earnings boom is real, but it is not broad. It is concentrated in a handful of artificial-intelligence giants — and that concentration is now the market's biggest strength and its biggest risk at the same time.

What Happened

The Wall Street Journal reported on Saturday that analysts expect S&P 500 companies to post a 30% year-over-year jump in third-quarter earnings, based on FactSet data. Two chip companies — Nvidia, the dominant maker of AI accelerators, and Micron Technology, the memory-chip maker whose high-bandwidth memory powers AI servers — are expected to deliver 34% of that entire increase.

FactSet's own Q3 analysis tells the same story: it ranks Micron and Nvidia as the top two contributors, ahead of Meta Platforms, EchoStar and Boeing, and says excluding just those two drops blended growth from 29.0% to 20.0%. LSEG, independently, also ranked Micron first for a second straight quarter, saying its earnings grew more than 1,000% and that Micron plus Nvidia account for nearly 35% of total growth.

Key Facts

• Headline growth: S&P 500 Q3 earnings are expected to rise about 30% year over year (FactSet, via The Wall Street Journal).
• Two-stock share: Nvidia and Micron alone account for 34% of that growth (Dow Jones Market Data analysis); LSEG puts their combined share at nearly 35%.
• Ten-stock share: Only 10 companies — including Broadcom and Meta Platforms, plus oil-and-gas giants that benefited from higher energy prices — account for roughly two-thirds of the profit growth.
• Without the top two: Excluding Micron and Nvidia, S&P 500 blended Q3 growth drops from 29.0% to 20.0% (FactSet).
• Micron's surge: Micron's earnings grew more than 1,000% year over year, making it the single largest contributor for a second consecutive quarter (LSEG).
• Magnificent 7 split: The Magnificent 7 are expected to grow earnings 33.2%, versus 27.7% for the other 493 companies — and within the Seven, Nvidia and Meta do most of the heavy lifting (FactSet).

Why It's Blowing Up

The timing is what makes this story travel. Meta's massive AI spending plans just helped trigger one of the Nasdaq's worst selloffs this year — the S&P 500 fell 0.5% for the week and the Nasdaq fell 0.7%, even though both sit only about 2.5% below all-time highs. Investors are asking: if AI profits are this concentrated, what happens if one or two names disappoint?

That is the risk in the Journal coverage: that AI ultimately will not deliver returns matching the enormous sums poured into data centers and chips. Analyst Ed Yardeni joked about the fear that "we're going to end up converting all these data centers into pickleball facilities." This is not a story about weak earnings — it is a story about narrow earnings, with very little margin for error at the top.

What's Next

The test arrives immediately. Next week is the busiest week of earnings season, with about one-third of the S&P 500 reporting, according to Reuters coverage. Alphabet and Microsoft report Wednesday and Amazon Thursday, with focus on AI capital-spending guidance — hyperscaler spending is expected to reach about $800 billion this year — and the Federal Reserve decides rates the same Wednesday. If the AI leaders deliver, concentration keeps supporting the index; if one stumbles, that same concentration could amplify the downside.

This post reports what happened and why markets reacted. It is not financial advice, and it does not recommend buying, selling or holding any security.

Sources

• The Wall Street Journal — The Earnings Boom Is Heavily Reliant on Just a Handful of Stocks
• FactSet Insight — Are Magnificent 7 Companies Still Top Contributors to S&P 500 Earnings Growth for Q3?
• LSEG Lipper Alpha Insight — Micron Overtakes Nvidia as Q3's Top Earnings Growth Contributor
• PANews (Reuters) — US Stocks Face Earnings Peak and Fed Decision Next Week as AI Rally Is Tested

FAQ

How much are S&P 500 Q3 earnings expected to grow?

Analysts expect S&P 500 third-quarter earnings to rise about 30% from a year ago, according to FactSet estimates reported by The Wall Street Journal on October 24, 2026.

How much of that growth comes from Nvidia and Micron?

Nvidia and Micron together account for 34% of the expected growth, according to a Dow Jones Market Data analysis. LSEG independently puts their combined share at nearly 35%.

What happens to earnings growth without Nvidia and Micron?

Excluding the two companies, the S&P 500's blended Q3 earnings growth rate falls from 29.0% to 20.0%, according to FactSet — still positive, but far less spectacular.

Why does earnings concentration matter?

When roughly two-thirds of profit growth comes from just 10 companies, the index depends heavily on those firms delivering. A disappointment from one major AI name can weigh on the whole market, as Meta's AI spending reaction showed this past week.