Micron Technology and Nvidia are making an unusually large contribution to the S&P 500’s projected third-quarter earnings growth. The index’s blended growth rate stood at 29% on Oct. 16, combining reported results with estimates for companies that had not yet released results. Removing the two chipmakers would reduce that rate to about 20%, leaving Micron and Nvidia responsible for roughly nine percentage points of growth.
Micron’s contribution is based on reported results. Its guidance indicates that further profit gains will rely increasingly on sales growth because operating margins have already reached exceptionally high levels.
Nvidia’s third-quarter contribution remains an estimate, but its latest results show the scale of the business behind it.
The earnings strength has not translated into matching stock performance. Nvidia shares were around $217 in the supplied analysis, about 9% below their Oct. 6 record close, while Micron traded near $905, roughly 25% below its June peak. Those valuations imply that investors remain concerned about the durability of memory pricing and the pace of artificial-intelligence infrastructure spending. The concentration also creates a broader market risk: if memory demand weakens or cloud companies reduce AI budgets, a disproportionate share of the S&P 500’s earnings growth could disappear. FactSet’s broader update showed that only 9% of index companies had reported third-quarter results by Oct. 16, so the 29% figure remained partly dependent on forecasts.