Micron led the way, contributing 26% of the Nasdaq-100's first-half returns and 17% of the S&P 500's gains, according to Jefferies

Micron's stock price quadrupled in the first half of the year and had a major impact on overall index returns.

A few major technology stocks were responsible for nearly all the gains in the Nasdaq-100 during the first six months of the year, according to an analyst.

As the Nasdaq-100 NDX climbed by about 20% in the first half of 2026, Micron Technology's $(MU)$ rally drove more than a quarter of those returns, Jefferies trading-desk analyst Jeffery Favuzza noted. The memory-chip stock quadrupled in the first half, enough to bring the company's market capitalization up to $1.3 trillion.

Other major contributors included Advanced Micro Devices $(AMD)$ and Intel $(INTC)$, two makers of central processing units that were responsible for 16% and 14%, respectively, of the index's returns. The next three contributors were chip-equipment companies Applied Materials $(AMAT)$, Lam Research $(LRCX)$ and KLA $(KLAC)$, respectively driving 10%, 9% and 6% of the index's gains.

Rounding out the top 10 are Sandisk $(SNDK)$ and Marvell Technology $(MRVL)$, each responsible for 5% of the index's returns, and Cisco Systems $(CSCO)$ and Western Digital $(WDC)$, each accounting for 4%.

When looking at the S&P 500 SPX, which was up almost 10% in the first half, a fairly similar grouping of 10 stocks accounted for 78% of returns, Favuzza noted. There, Micron's contribution was slightly smaller but still in the lead at 17%, while Alphabet (8%), Nvidia (6%) and Apple (5%) broke into the top 10.

Ssome of those hot stocks were fading in premarket action on Wednesday, the first day of the second half, Favuzza noted. Meanwhile, beaten-down software stocks like ServiceNow (NOW), Salesforce (CRM) and Intuit $(INTU)$, which were among the first half's biggest losers, are set to bounce.

"The most glaring dynamic is the leaders/laggards rotation that we're currently seeing as we flip the calendar," Favuzza wrote.

Shares of both ServiceNow and Salesforce were up 4% in premarket action after upgrades at Guggenheim.

"While we do see AI as a significant risk and view [Salesforce] as a company likely to be negatively impacted by the advent of agentic AI, we believe the Armageddon scenario currently priced into the stock is misaligned with reality," Guggenheim's John DiFucci wrote as he lifted his rating on the stock to buy from neutral.

-Emily Bary

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July 01, 2026 09:34 ET (13:34 GMT)

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