Three-Line Briefing
- Vertiv’s emergence as an S&P 500 inclusion candidate is a supply-demand (order flow) event that first sparks expectations of new passive-fund buying, ahead of its AI data-center revenue outlook.
- According to MarketWatch’s March 6, 2026 report, Vertiv’s market capitalization was $94.6 billion and Reddit’s was $26.9 billion.
- Both companies exceeded the $22.7 billion market-capitalization threshold for new additions at the time, but final selection is at the index committee’s discretion, and there may be no changes.
What Changes
The S&P 500’s regular rebalancing is the process by which S&P Dow Jones Indices reviews and replaces stocks (tickers) in the index representing the U.S. large-cap stock market. If inclusion is approved, ETFs and index funds tracking the index must add the new stock (ticker) to their portfolios when the change takes effect. That is why short-term buying demand can emerge even if earnings estimates remain unchanged.
The key candidates are data-center power and cooling infrastructure provider Vertiv and social-media platform Reddit. Vertiv is positioned to benefit as AI server expansion drives demand for power supply and thermal management. As Nvidia accelerator shipments increase, server-rack power density rises, prompting data-center operators to expand cooling and power equipment together. Expectations of index inclusion add another layer of passive supply-demand (order flow) to this industry-growth narrative.
Reddit follows a different path. The investment case for Reddit depends on its ability to convert its user base into advertising and data-licensing revenue. S&P 500 inclusion would not change the company’s competitive strength, but it could broaden institutional investors’ ownership base and trading liquidity. However, as in the analysis cited by MarketWatch, the committee may favor promoting existing mid-cap index constituents, so the result cannot be predicted from a new candidate’s market capitalization alone.
Putting the Numbers in Context
In MarketWatch’s March 6 report, Vertiv’s $94.6 billion market capitalization was more than four times the $22.7 billion inclusion floor at the time. Reddit’s $26.9 billion was also $4.2 billion above the threshold. Vertiv has a substantial size cushion, but Reddit’s buffer could shrink quickly if a sharp share-price decline pushes its market capitalization below $22.7 billion.
On the other side are Lamb Weston, Paycom Software, Match Group, EPAM Systems and Molina Healthcare. MarketWatch identified them as lower-market-capitalization S&P 500 constituents facing possible demotion. Existing constituents are not automatically removed simply because they fall below the inclusion floor. Ultimately, prices reflect not only a candidate’s absolute size but also the number of vacancies, industry-sector balance and the committee’s need to make replacements.
Potential Winners and Losers
- Vertiv: A direct candidate for passive buying if included, with an earnings driver from AI data-center equipment demand as well. However, if the stock has risen sharply before the announcement, profit-taking could overlap with the actual inclusion date.
- Reddit: Inclusion would improve institutional investors’ access and liquidity. Its smaller market-capitalization cushion than Vertiv’s means share-price volatility could have a greater effect on inclusion expectations.
- Lamb Weston, Paycom Software and Match Group: Lower-market-capitalization stocks could face selling pressure from index-tracking funds if named as removal candidates.
- EPAM Systems and Molina Healthcare: Mechanical selling pressure would materialize only if they are confirmed as the actual replacement stocks. A candidate list alone is not evidence that their earnings value has been impaired.
Risk Check
- The index committee may make no changes at all in its regular review. Being a candidate is different from receiving an inclusion decision.
- If inclusion expectations have already been priced into shares, profit-taking immediately after the announcement could exceed anticipated passive demand.
- For Vertiv, if AI capital spending slows, weaker data-center orders could weigh on valuation more heavily than index-related supply-demand (order flow).
- Even if Reddit maintains the market-capitalization threshold, it could lose out in the committee’s assessment of profitability, liquidity and industry-sector composition.
Bottom Line
Vertiv and Reddit joining the S&P 500 would be a positive catalyst for short-term supply-demand (order flow), but the stocks’ next trend will depend on whether inclusion is actually confirmed after the regular-rebalance announcement and whether data-center orders and advertising monetization sustain expectations. Kang Si-hyun, editorial board member, One Day Trading
Frequently Asked Questions
Why might Vertiv rise if it joins the S&P 500?
ETFs and index funds tracking the S&P 500 would need to buy Vertiv shares when the inclusion takes effect. However, some expected buying may be priced in before the announcement, so confirmed inclusion does not guarantee a gain.
What are Reddit’s requirements for S&P 500 inclusion?
According to MarketWatch’s March 6, 2026 report, Reddit had a market capitalization of $26.9 billion, above the $22.7 billion floor at the time. Beyond market capitalization, it must meet requirements including profitability and liquidity and pass the index committee’s discretionary review.
Should investors sell an S&P 500 removal candidate immediately?
Removal does not mean a company’s operating value disappears immediately; it means passive funds are no longer required to hold the stock. Investment decisions should consider not only supply-demand (order flow) between the removal announcement and effective date but also subsequent earnings and valuation.
This article is automatically summarized and analyzed based on the original news report. View original report (MarketWatch)
