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

-0.57% close to close Open Argus

Details

News Market Reaction – SPGI

In the Jul 10 session, SPGI declined 0.57%, reflecting a mild negative market reaction.

Data tracked by StockTitan Argus on the day of publication.

Market Context

S&P Dow Jones Indices’ decision to add Solaris to the S&P SmallCap 600 highlights ongoing benchmark ...

Analysis

S&P Dow Jones Indices’ decision to add Solaris to the S&P SmallCap 600 highlights ongoing benchmark reshuffling tied to M&A. For S&P Global, index franchise activity complements recent structural moves; investors may watch how future rebalances and product launches affect demand.

Key Figures

Index effective date: July 15, 2026 Index replaced company: Catalyst Pharmaceuticals removed First index creation year: 1884

Index effective date

July 15, 2026

Date Solaris Energy Infrastructure joins S&P SmallCap 600

Index replaced company

Catalyst Pharmaceuticals removed

Deletion from S&P SmallCap 600 on July 15, 2026

First index creation year

1884

Year Charles Dow invented the first index

Historical Context

5 past events · Latest: Jul 06

5 events

1. Jul 06

   Earnings call scheduling

   24h Move

   +1.7%

   Set reporting date and time for second quarter 2026 earnings call.

2. Jul 06

   Pro forma financials

   24h Move

   +1.7%

   Published recast results excluding Mobility division and updated segment data.

3. Jul 06

   Operating model update

   24h Move

   +1.7%

   Reorganized Market Intelligence around new verticals with leadership changes.

4. Jul 02

   Index constituent changes

   24h Move

   +1.7%

   Announced additions to S&P SmallCap 600 tied to spin-off and acquisition.

5. Jul 01

   Mobility spin-off completion

   24h Move

   +1.9%

   Completed tax-free spin-off of Mobility Global and began standalone trading.

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 500, dow jones industrial average

4 terms

s&p smallcap 600 financial

"will replace Catalyst Pharmaceuticals Inc. (NASD: CPRX) in the S&P SmallCap 600 effective"

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

"Effective Date | Index Name | Action | Company Name | Ticker | GICS Sector"

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 500 financial

"such as the S&P 500 and the Dow Jones Industrial Average."

The S&P 500 is a broad stock market index that tracks the performance of 500 large U.S. companies, weighted so bigger firms have a larger impact. Investors use it like a thermometer or benchmark to judge how the overall U.S. stock market or a portfolio is doing; movements in the index influence investor sentiment, fund performance, and many passive investment products that aim to match its returns.

View in glossary

dow jones industrial average financial

"such as the S&P 500 and the Dow Jones Industrial Average."

A stock market index that tracks the share prices of a small group of large, well-known companies to give a quick snapshot of how the broader market is doing. Think of it like a thermometer for the stock market: it uses a handful of heavyweight firms as representative samples to show whether investor sentiment is rising or falling, which helps investors gauge market trends and compare performance over time.

View in glossary

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.