Solaris Energy Infrastructure Set to Join S&P SmallCap 600

Solaris Energy Infrastructure (NYSE: SEI) will join the S&P SmallCap 600, replacing Catalyst Pharmaceuticals (NASD: CPRX), effective before the market opens on July 15, 2026.

Rhea-AI Summary

Solaris Energy Infrastructure (NYSE: SEI) will join the S&P SmallCap 600, replacing Catalyst Pharmaceuticals (NASD: CPRX), effective before the market opens on July 15, 2026. Catalyst is being removed as Angelini Pharma is acquiring the company, subject to final closing conditions.

Positive

• SEI added to S&P SmallCap 600 effective July 15, 2026
• Energy sector representation in S&P SmallCap 600 via Solaris Energy Infrastructure

Negative

• None.

Argus Jul 10 session 7 alerts

+4.85% close to close 1.7x rel. volume Open Argus

Details

Market move: SEI +4.85% in the Jul 10 session. S&P SmallCap 600 index inclusion

+2.1% Peak in 4 hr 32 min

$4.06B Mkt Cap at Peak Alert

On Jul 10, the first trading day after this news, SEI closed 4.85% above the previous close. Argus tracked a peak move of +2.1% during that session. Our momentum scanner recorded 7 alerts for this stock that day. That session’s volume was 1.7x the stock’s average daily volume.

Data tracked by StockTitan Argus for the Jul 10 session.

Key Figures

Index inclusion effective date: July 15, 2026

Index inclusion effective date

July 15, 2026

SEI added to S&P SmallCap 600 before market open

Historical Context

5 past events · Latest: Jul 06

5 events

1. Jul 06

   M&A acquisition

   24h Move

   +0.4%

   Closed GESA acquisition using cash and stock, expected to be accretive.

2. May 13

   Financing & contract

   24h Move

   +1.3%

   Completed nearly $2 billion in financing and expanded a major power contract.

3. May 05

   Debt offering pricing

   24h Move

   +2.3%

   Priced $1.3 billion 6.375% senior notes due 2031 at par.

4. May 05

   Debt offering launch

   24h Move

   +1.6%

   Announced intent to offer $1.3 billion senior notes due 2031.

5. Apr 27

   Earnings report

   24h Move

   +5.4%

   Reported Q1 2026 growth, raised EBITDA guidance, signed large long-term contract.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Key Terms

s&p smallcap 600, gics sector, s&p dow jones indices

3 terms

s&p smallcap 600 financial

"July 15, 2026 | S&P SmallCap 600 | Addition | Solaris Energy Infrastructure"

A stock market index made up of 600 small-cap U.S. companies chosen to represent the performance of smaller publicly traded firms. It matters to investors because it acts like a temperature gauge for the small-company segment of the market, serving as a benchmark for fund managers, a basis for index funds and ETFs, and a way to compare returns and risk when building a diversified portfolio.

gics sector financial

"Ticker | GICS Sector -------------------------------------------------------------------------- July 15, 2026"

GICS sector is one of the major industry groupings from the Global Industry Classification Standard, a system that sorts companies into consistent categories (like Technology or Health Care) based on the primary business they do. Investors use these sectors like folders in a filing cabinet to compare companies, build diversified portfolios, and track how whole parts of the market are performing rather than focusing on single stocks.

s&p dow jones indices financial

"ABOUT S&P DOW JONES INDICES S&P Dow Jones Indices is the largest global resource"

S&P Dow Jones Indices is the organization that creates and maintains widely used stock market benchmarks, such as broad market and sector indexes. Think of it as the scorekeeper that measures how groups of stocks are performing; investors and fund managers use these benchmarks to compare results, build passive funds and ETFs, and gauge overall market health, so index changes can affect investment flows and portfolio strategies.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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NEW YORK, July 9, 2026 /PRNewswire/ -- Solaris Energy Infrastructure Inc. (NYSE: SEI) will replace Catalyst Pharmaceuticals Inc. (NASD: CPRX) in the S&P SmallCap 600 effective prior to the opening of trading on Wednesday, July 15. Angelini Pharma S.p.A. is acquiring Catalyst Pharmaceuticals in a deal expected to close soon, pending final closing conditions.

Following is a summary of the changes that will take place prior to the open of trading on the effective date:

Effective Date	Index Name		Action	Company Name	Ticker	GICS Sector
July 15, 2026	S&P SmallCap 600	Addition		Solaris Energy Infrastructure	SEI	Energy
July 15, 2026	S&P SmallCap 600	Deletion		Catalyst Pharmaceuticals	CPRX	Health Care

ABOUT S&P DOW JONES INDICES

S&P Dow Jones Indices is the largest global resource for essential index-based concepts, data and research, and home to iconic financial market indicators, such as the S&P 500® and the Dow Jones Industrial Average®. More assets are invested in products based on our indices than products based on indices from any other provider in the world. Since Charles Dow invented the first index in 1884, S&P DJI has been innovating and developing indices across the spectrum of asset classes helping to define the way investors measure and trade the markets.

S&P Dow Jones Indices is a division of S&P Global (NYSE: SPGI), which provides essential intelligence for individuals, companies, and governments to make decisions with confidence. For more information, visit www.spglobal.com/spdji/en/.

FOR MORE INFORMATION:

S&P Dow Jones Indices
index_services@spglobal.com

Media Inquiries
spdji.comms@spglobal.com

View original content:https://www.prnewswire.com/news-releases/solaris-energy-infrastructure-set-to-join-sp-smallcap-600-302822362.html

SOURCE S&P Dow Jones Indices

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What change is occurring for Solaris Energy Infrastructure (NYSE: SEI) on July 15, 2026?

Solaris Energy Infrastructure will be added to the S&P SmallCap 600 index before trading opens on July 15, 2026. According to S&P Dow Jones Indices, SEI will replace Catalyst Pharmaceuticals in the benchmark.

Why is Catalyst Pharmaceuticals (NASDAQ: CPRX) being removed from the S&P SmallCap 600?

Catalyst Pharmaceuticals will be deleted from the S&P SmallCap 600 on July 15, 2026. According to S&P Dow Jones Indices, this follows Catalyst’s planned acquisition by Angelini Pharma, pending final closing conditions.

Which index will include Solaris Energy Infrastructure (SEI) after July 15, 2026?

Solaris Energy Infrastructure will be included in the S&P SmallCap 600 index. According to S&P Dow Jones Indices, SEI will join the index as an Energy sector constituent effective prior to the market open on July 15, 2026.

What sector classification will SEI have in the S&P SmallCap 600 index?

Solaris Energy Infrastructure will be classified in the Energy sector within the S&P SmallCap 600. According to S&P Dow Jones Indices, SEI joins the index as an Energy company, replacing Health Care company Catalyst Pharmaceuticals.

When does the replacement of CPRX by SEI in the S&P SmallCap 600 take effect?

The index replacement is effective before the opening of trading on July 15, 2026. According to S&P Dow Jones Indices, Solaris Energy Infrastructure will be added and Catalyst Pharmaceuticals deleted on that date.