Four AI stocks join the S&P 500, prompting a buy, hold, or pass debate among investors

The S&P 500 just got an AI makeover. S&P Dow Jones Indices added four companies deeply tied to artificial intelligence infrastructure to the benchmark index effective March 23, 2026: Vertiv Holdings, Lumentum, Coherent, and EchoStar. They replaced Match Group, Molina Healthcare, Lamb Weston, and Paycom Software. The numbers behind the new entrants Lumentum, which makes optical components critical to data center networking, saw its shares surge more than 800% in the 12 months preceding the announcement. Coherent, operating in a similar optical networking niche, gained 262% over the same period. EchoStar climbed 274% year-over-year, buoyed by its spectrum assets becoming increasingly valuable in an AI-connected world. A key catalyst behind the optical networking rally: Nvidia committed $2 billion in investments to Lumentum and Coherent, along with substantial purchase agreements linked to AI data center expansion. Why the index swap matters Getting added to the S&P 500 forces hundreds of billions of dollars in passive fund flows. Every index fund and ETF tracking the S&P 500 must buy shares of new entrants and sell the companies being removed. Vanguard’s S&P 500 E...