The Nasdaq-100 posted roughly a 20% gain in the first half of 2026. Ten stocks, almost all of them AI-adjacent chipmakers and memory hardware companies, were responsible for nearly the entire move.
Micron did the heavy lifting
Jefferies analyst Jeffery Favuzza put numbers to what many traders had been sensing. Micron Technology contributed 26% of the Nasdaq-100’s total returns in H1 2026, after its stock quadrupled over the same period, pushing its market cap to $1.3 trillion.
The full Jefferies breakdown of top contributors reads like an AI infrastructure shopping list. Advanced Micro Devices came in second at 16% of index returns, followed by Intel at 14%, Applied Materials at 10%, Lam Research at 9%, KLA Corporation at 6%, Sandisk at 5%, Marvell Technology at 5%, Cisco at 4%, and Western Digital at 4%.
Add those up and you get nearly 99% of the index’s H1 gains attributable to ten names.
