Carvana, CRH and Comfort Systems USA Join the S&P 500: What the December 2025 Rebalance Means for Investors

On December 6, 2025, investors are digesting a major shake-up to the world’s most-watched stock index. After the closing bell on Friday, December 5, S&P Dow Jones Indices announced that Carvana Co. (CVNA), CRH plc (CRH) and Comfort Systems USA (FIX) will be added to the S&P 500 as part of its quarterly rebalance, effective before the market opens on Monday, December 22, 2025. ^[1]

The move caps a dramatic comeback story for online auto retailer Carvana, recognizes record profits at building-materials giant CRH, and rewards rapid growth at mechanical and electrical contractor Comfort Systems. All three stocks jumped in after-hours trading following the announcement, while the companies they are replacing slipped. ^[2]

Below is a breakdown of what changed, why these three companies got the nod, who lost out, and what the “index effect” could mean for investors as of December 6, 2025.

The New S&P 500 Lineup: Additions, Deletions and Ripple Effects

New S&P 500 members

According to the official press release from S&P Dow Jones Indices, the following three companies will join the S&P 500 effective December 22: ^[3]

CRH plc (CRH) – Materials
Carvana Co. (CVNA) – Consumer Discretionary
Comfort Systems USA (FIX) – Industrials

These additions are part of the index committee’s regular quarterly review, which aims to keep the S&P 500 representative of the large‑cap U.S. equity market in terms of size, sector and liquidity.

Who’s being removed from the S&P 500

To make room, three existing S&P 500 constituents will be removed from the benchmark and moved down to the small‑cap index: ^[4]

LKQ Corp. (LKQ) – Consumer Discretionary
Solstice Advanced Materials (SOLS) – Materials
Mohawk Industries (MHK) – Consumer Discretionary

All three will join the S&P SmallCap 600, a demotion that often means reduced index-fund demand and less visibility with large‑cap-focused investors. The affected stocks traded slightly lower following the news. ^[5]

Chain reaction in the MidCap 400 and SmallCap 600

The reshuffle doesn’t stop at the S&P 500. The same announcement outlines sweeping changes to the S&P MidCap 400 and S&P SmallCap 600: ^[6]

Comfort Systems USA (FIX) is deleted from the S&P MidCap 400 as it moves up to the S&P 500.
New S&P MidCap 400 additions include:
- UL Solutions (ULS)
- Pinterest (PINS)
- Booz Allen Hamilton Holding (BAH)
- SPX Technologies (SPXC)
- Dycom Industries (DY)
- BorgWarner (BWA)
- Hecla Mining (HL)
The MidCap 400 simultaneously drops several names – including Under Armour’s A and C share classes (UAA, UA), Power Integrations (POWI), Perrigo (PRGO), Iridium Communications (IRDM), Marriott Vacations Worldwide (VAC) and Insperity (NSP) – many of which then reappear as additions to the SmallCap 600.
In the S&P SmallCap 600, new entrants also include Primoris Services (PRIM), Casella Waste Systems (CWST), Indivior (INDV) and Hawaiian Electric (HE), alongside the demoted former S&P 500 names LKQ, Solstice and Mohawk.

The net effect is a broad rebalancing across the S&P index family designed to keep each benchmark aligned with its intended market-cap range and sector mix. ^[7]

Carvana: From Distressed Bet to S&P 500 Comeback Story

Just three years ago, Carvana was widely viewed as a meme‑stock casualty, hammered by rising rates, used‑car price volatility and a heavy debt load. Fast‑forward to late 2025, and the company is being rewarded with a seat in the S&P 500.

Explosive growth and a profitability turnaround

Carvana has spent the last two years overhauling its balance sheet and operations. In 2025, the company reported:

Q2 2025: 143,280 retail units sold (+~41% year over year) and revenue of $4.84 billion, both record highs. ^[8]
Q3 2025: revenue of $5.65 billion, up roughly 55% from a year earlier, with net income of $263 million and a 4.7% net margin, an industry‑leading level for auto retail. ^[9]

Analysts and investors have taken notice. One recent analysis described Carvana as a “true disruptor” in the used‑car market, pointing to its digital-first platform and strong execution, even as competition from legacy dealerships and online rivals intensifies. ^[10]

A stock that has already roared back

Carvana’s share price has staged a remarkable recovery in 2025:

The stock has roughly doubled this year, massively outperforming the broader S&P 500. ^[11]
After Friday’s S&P 500 announcement, CVNA jumped about 9–10% in after-hours trade, according to multiple market reports. ^[12]

That move fits the historical pattern: index additions often experience a short-term price bump as passive index funds and closet indexers are forced to buy the shares. Research frequently cites typical jumps in the mid‑single‑digit range around inclusion, and Carvana’s reaction landed near the high end of that spectrum. ^[13]

Why the S&P 500 committee likes Carvana now

Inclusion in the S&P 500 requires companies to meet stringent criteria, including:

U.S. listing and regulatory compliance
Minimum market capitalization (about $22.7 billion as of mid‑2025)
Positive GAAP earnings over the most recent quarter and the sum of the prior four quarters
Adequate liquidity and public float ^[14]

Carvana’s combination of rapid revenue growth, sustained profitability and rising market cap now ticks those boxes. Its presence in the index also increases exposure to the online retail and digital auto theme within the consumer discretionary sector.

CRH: Infrastructure and Construction Play Steps Onto Center Stage

CRH plc, headquartered in Ireland but listed on the NYSE, is one of the world’s largest building‑materials companies, supplying aggregates, cement, asphalt and other essential products for roads, infrastructure and commercial construction.

Record earnings and shareholder returns

CRH’s latest results show why it has earned a spot in the S&P 500:

Q3 2025 revenue:$11.1 billion, up about 5% year over year.
Net income:$1.5 billion, an increase of around 9%.
Net income margin: about 13.7%, up 50 basis points from the prior year.
Adjusted EBITDA:$2.7 billion, up 10%, with margin expanding to roughly 24.3%. ^[15]

The company has been aggressively returning cash to shareholders via buybacks and dividends, while also pursuing billions of dollars in acquisitions to consolidate its position in key markets. ^[16]

Market reaction: a solid pop on the news

After the S&P 500 announcement, CRH’s U.S.-listed shares gained roughly 6–7% in after-hours trading, according to early reports, reflecting the expected inflows from index funds and the market’s approval of the promotion. ^[17]

A pure play on infrastructure megatrends

CRH’s inclusion also strengthens the Materials sleeve of the S&P 500 at a time when infrastructure demand – from roads and bridges to energy and industrial projects – is expected to remain robust into 2026 and beyond. Company commentary highlights positive pricing, solid demand and ongoing acquisitions as key drivers, and recent analyses point to record results and a 6% dividend increase as evidence of financial strength. ^[18]

For index investors, CRH adds more direct exposure to infrastructure and construction spending, themes that are central to many long‑term macro forecasts.

Comfort Systems USA: Riding the HVAC and Data-Center Boom

Comfort Systems USA is a mechanical, electrical and plumbing (MEP) contractor best known for large‑scale HVAC, industrial and data‑center projects. It has quietly become one of the market’s standout growth stories.

Blowout earnings and a soaring stock

Comfort Systems has delivered a string of record quarters in 2025:

Q2 2025: net income of $230.8 million, up from $134.0 million a year earlier. ^[19]
Q3 2025: net income of about $291.6 million, nearly doubling year over year, with operating income up 86% and free cash flow north of $500 million for the quarter. ^[20]
Revenue growth has been running in the 20–30%+ range, driven by strong demand for complex infrastructure projects and data‑center work. ^[21]

Analysts note that Comfort Systems’ share price has jumped more than 100% over the past year, reflecting this sustained growth and improving margins. ^[22]

Index promotion from mid-cap to large-cap

Comfort Systems was previously part of the S&P MidCap 400. The new rebalance removes it from the MidCap 400 and adds it to the S&P 500, a clear signal that the company is now considered a large‑cap industrial player. ^[23]

On the announcement, FIX rose about 1–2% after hours, a more modest move than Carvana or CRH but still reflective of expected index inflows and growing institutional interest. ^[24]

Leveraging the data-center and HVAC supercycle

Coverage of Comfort Systems increasingly emphasizes its role in data centers, advanced industrial facilities and large-scale HVAC retrofits. One recent industry piece highlighted 33% year‑over‑year revenue growth tied to a modular “Lego‑like” construction model that helps it deliver complex projects efficiently – including the cooling and power infrastructure that AI‑heavy data centers require. ^[25]

For investors, Comfort Systems’ promotion gives the S&P 500 additional exposure to the AI and cloud infrastructure build‑out, but through a picks‑and‑shovels contractor rather than another mega‑cap tech name.

Winners, Losers and the Notable Snubs

The demoted S&P 500 names

While the headlines focus on the new entrants, three companies are losing S&P 500 status:

LKQ (LKQ) – auto-parts distributor
Solstice Advanced Materials (SOLS) – materials
Mohawk Industries (MHK) – flooring and building products

Each will join the S&P SmallCap 600. Early trading shows mild declines in their shares, consistent with the idea that dropping out of the S&P 500 tends to reduce index-fund ownership and liquidity over time. ^[26]

Mid-cap winners: Pinterest, Booz Allen, UL Solutions and more

Among mid‑cap names, several companies are moving up into the S&P MidCap 400, including: UL Solutions, Pinterest, Booz Allen Hamilton, SPX Technologies, Dycom, BorgWarner and Hecla Mining. ^[27]

These promotions often bring a smaller but still meaningful wave of buying from ETFs and mutual funds that track the MidCap 400, while strengthening index exposure to testing and certification (UL Solutions), digital advertising and social media (Pinterest) and defense and consulting (Booz Allen).

The stocks that didn’t make the cut

Ahead of the announcement, speculation swirled around a long list of potential additions. Research from Wall Street strategists and financial media cited candidates such as: ^[28]

Vertiv Holdings (VRT) – data-center power and cooling
SoFi Technologies (SOFI) – fintech and digital banking
Ares Management (ARES) – alternative asset manager
Alnylam Pharmaceuticals (ALNY) – biotech
Carvana, Cheniere Energy, Coupang, Ferguson Enterprises and others

Some articles explicitly flagged Vertiv and SoFi as “notable exclusions” after the final decision, as both had strong price momentum and met size and liquidity thresholds but were passed over in favor of CRH, Carvana and Comfort Systems. ^[29]

MarketWatch also highlighted that several tech and crypto‑adjacent names – including MicroStrategy, Marvell Technology and Reddit – were left out this time, underlining the committee’s preference in this rebalance for more cash‑generative, infrastructure‑linked businesses rather than additional high‑beta tech exposure. ^[30]

The “Index Effect”: Why S&P 500 Inclusion Matters

Forced buying and short-term price pops

When a company enters the S&P 500, index-tracking funds must buy it, while funds benchmarked to the S&P often adjust positions to avoid straying too far from the index. This mechanical demand can create a short-term demand shock:

Historically, studies and market commentary suggest S&P 500 additions often see 3–7% price jumps around the announcement and effective dates due to these passive flows. ^[31]
Carvana’s roughly 9–10% after-hours surge, CRH’s mid‑single‑digit pop and Comfort Systems’ smaller but positive move all fit that pattern. ^[32]

A separate AI‑driven analysis of the event notes that while index inclusion improves liquidity and can narrow valuation gaps (especially for smaller companies), it can also push prices temporarily above fundamentals, increasing the risk of mean reversion once the initial buying wave passes. ^[33]

How the additions shape sector exposure

The December 22 changes will slightly tweak the S&P 500’s sector mix: ^[34]

Consumer Discretionary gains exposure to a high‑growth online auto retailer (Carvana) while losing LKQ and Mohawk.
Materials gets a major global building‑materials producer (CRH) while also losing Solstice.
Industrials picks up Comfort Systems, a fast‑growing MEP contractor tied to data centers and infrastructure, with no direct industrial names leaving the index.

While the weight shifts are small in the context of a 500‑stock, multi‑trillion‑dollar benchmark, they matter for sector‑focused investors and for passive funds that slice the market by industry themes.

A strong macro backdrop for the announcement

The index changes arrive at the end of a relatively upbeat week for U.S. equities. The S&P 500 and Nasdaq recently notched their fourth straight day of gains, helped by in‑line inflation data that boosted expectations for Federal Reserve rate cuts in 2026. ^[35]

In that context, the S&P 500 rebalance – and the sharp moves in Carvana, CRH and Comfort Systems – is landing on a market already primed for risk‑on sentiment and momentum in growth and infrastructure names.

What It Means for Investors Now

For index and ETF investors

Index trackers that follow the S&P 500 will gradually adjust their holdings, often close to the December 22 effective date to minimize tracking error.
S&P 500 ETFs will buy Carvana, CRH and Comfort Systems and sell LKQ, Solstice and Mohawk, while MidCap 400 and SmallCap 600 products juggle a longer list of additions and deletions. ^[36]

For most long‑term passive investors, these shifts happen automatically; the main impact is slightly different sector and factor exposure inside broad‑market funds.

For active investors and traders

For stock pickers, the S&P 500 announcement is both a catalyst and a signal:

It confirms that Carvana, CRH and Comfort Systems now meet size, liquidity and profitability thresholds considered appropriate for the blue‑chip benchmark. ^[37]
It highlights ongoing themes:
- the digitalization of auto retail (Carvana),
- global infrastructure and construction spending (CRH), and
- the HVAC/data‑center build‑out (Comfort Systems). ^[38]

At the same time, research from AInvest and others stresses that index inclusion alone should not be a stand‑alone investment thesis. Valuations, balance-sheet strength, competitive position and macro sensitivity all remain crucial, especially after a sharp, flow‑driven price move. ^[39]

Bottom Line

The December 2025 S&P 500 rebalance is more than a technical footnote. It:

Elevates Carvana, CRH and Comfort Systems USA into the U.S. large‑cap elite,
Shifts capital toward companies tied to infrastructure, construction and digital auto retail, and
Reminds investors how powerful index mechanics can be in the short term.

For Carvana, the move crowns a high‑risk turnaround that has so far delivered soaring revenues and a return to profitability. For CRH, it validates a strategy built around infrastructure megatrends, margin expansion and shareholder returns. For Comfort Systems, it confirms that a once‑overlooked contractor is now a central player in the data‑center and HVAC supercycle.

Still, the same message applies to all three: S&P 500 inclusion provides liquidity and visibility, not a guarantee of future outperformance. Investors watching this story unfold on December 6, 2025, should treat the rebalance as a catalyst to dig deeper into fundamentals, not as a substitute for them.