S&P 500 Rebalance Highlights AI Infrastructure Shift

S&P Global has announced four new additions to the S&P 500 as part of its quarterly rebalance, reinforcing the growing dominance of AI infrastructure within the benchmark.

The index provider reviews constituents every quarter based on market capitalisation, profitability, liquidity, and sector balance to ensure the index reflects the most representative US large-cap companies.

Vertiv Holdings, Lumentum Holdings, Coherent Corp., and EchoStar Corporation will join the index, replacing Match Group, Molina Healthcare, Lamb Weston Holdings, and Paycom Software. The changes take effect before the market opens on 23 March.

With trillions of dollars benchmarked to the S&P 500, index inclusion typically triggers passive fund inflows. Markets responded quickly, with the four incoming stocks rising by an average of 8% following the announcement.

Notably, three of the four additions are directly tied to the AI build-out, highlighting how sustained investment in artificial intelligence is reshaping the composition of the index.

The latest rebalance reflects a broader structural shift that AI is becoming foundational to market leadership.

Big Tech is guiding for as much as $900bn in AI-related capital expenditure this year, driving demand across power systems, cooling solutions, and high-speed optical connectivity. Here’s more information on the newest members of the index:

Vertiv

Vertiv specialises in critical digital infrastructure, including power and thermal management systems for high-density data centres.

Demand has surged alongside AI workloads, particularly for liquid cooling and high-capacity power solutions. In its latest results, the company reported 252% year-on-year growth in organic orders, with backlog reaching $15bn, up 109%.

A book-to-bill ratio of 2.9x and forward guidance of up to 29% organic growth underscore strong demand visibility.

Vertiv’s inclusion reflects its central role in enabling hyperscalerexpansion and positions it as a key beneficiary of continued AI infrastructure investment.

Lumentum

Lumentum develops advanced optical components essential for high-speed data transmission in AI systems.

The company recently secured a multi-year partnership with Nvidia, including a $2bn investment to expand manufacturing and R&D capacity. The deal also includes multibillion-dollar purchase commitments.

The addition to the S&P 500 elevates the importance of optical technologies as a core layer in AI infrastructure, with Lumentumpositioned as a critical supplier in scaling next-generation data centre networks.

Coherent

Coherent focuses on photonics and laser technologies, particularly silicon photonics and optical interconnects used in large-scale AI clusters.

Like Lumentum, it has secured a $2bn strategic partnership with Nvidia, aimed at advancing high-performance optical solutions and expanding US manufacturing.

The company’s repositioning toward AI-driven applications has aligned it with long-term demand trends, and its inclusion signals growing recognition of photonics as essential to AI scalability and efficiency.

EchoStar

EchoStar is the only new entrant not directly tied to AI infrastructure.

The company operates in satellite communications, broadband, and video services through its DISH network. Its inclusion provides sector balance, adding exposure to communications within an otherwise AI-heavy rebalance.

Despite this distinction, EchoStar has also delivered strong performance, supported by resilience in telecom services amid broader technological shifts.

Market Outlook

The inclusion of AI-linked infrastructure providers into the S&P 500 shows that there’s a deepening shift from software-led AI narratives toward the physical backbone of compute.

In the near term, newly added names may benefit from index-driven buying and momentum flows, but valuations are already reflecting strong forward demand.

Looking ahead, the key question for investors is whether the current pace of AI capital expenditure, projected at hundreds of billions annually, can be sustained without overcapacity or margin compression.

If spending holds, companies tied to power, cooling, and optical connectivity are likely to remain structurally advantaged. However, any slowdown in hyperscaler investment could expose these names to sharp repricing.