Sandisk Set to Join S&P 500; Upwork, First Interstate BancSystem, PTC Therapeutics to Join S&P SmallCap 600

Rhea-AI Summary

Gildan (NYSE: GIL) and several companies will move between S&P indices effective late November–early December 2025. Sandisk (SNDK) is being added to the S&P 500 on November 28, 2025, with PTC Therapeutics (PTCT) joining the S&P SmallCap 600 the same day. Upwork (UPWK) and First Interstate BancSystem (FIBK) also join the SmallCap 600 on November 28 and December 2, 2025, respectively; Interpublic, Premier and Hanesbrands will be removed.

Positive

• Sandisk added to S&P 500 on November 28, 2025
• PTC Therapeutics added to S&P SmallCap 600 on November 28, 2025
• Upwork added to S&P SmallCap 600 on November 28, 2025
• First Interstate BancSystem added to S&P SmallCap 600 on December 2, 2025

Negative

• Interpublic deleted from S&P 500 on November 28, 2025
• Hanesbrands deleted from S&P SmallCap 600 on December 2, 2025
• Premier deleted from S&P SmallCap 600 on November 28, 2025

Key Figures

Effective date: November 28, 2025 Effective date: December 02, 2025

2 metrics

Effective date November 28, 2025 Index changes for S&P 500 and S&P SmallCap 600

Effective date December 02, 2025 Additional S&P SmallCap 600 changes

Market Reality Check

Price: $76.94 Vol: Volume 3,217,364 vs 20-da...

low vol

$76.94 Last Close

Volume Volume 3,217,364 vs 20-day average 5,066,215 (relative volume 0.64x). low

Technical Price 76.00 is trading slightly below 200-day MA of 76.37.

Peers on Argus

OMC was up 1.65% while key peers were mixed: TTD +5.31%, APP +5.51%, WPP +3.54%,...

OMC was up 1.65% while key peers were mixed: TTD +5.31%, APP +5.51%, WPP +3.54%, QMMM +19.44%, and IPG -0.36%, suggesting stock-specific dynamics around the index-change and M&A news rather than a uniform sector move.

Historical Context

5 past events · Latest: Apr 02 (Neutral)

Pattern 5 events

Date	Event	Sentiment	Move	Catalyst
Apr 02	Earnings schedule	Neutral	+1.5%	Announced date and time for Q1 2026 earnings release and call.
Apr 01	Capability launch	Positive	-0.1%	Launched unified Adobe practice via Credera and LeapPoint integration.
Mar 26	Industry ranking	Positive	-0.6%	Named best performing global media group with #1 ranking worldwide.
Mar 24	Innovation awards	Positive	-0.3%	Multiple agencies recognized on Fast Company’s Most Innovative Companies list.
Mar 17	Marketing campaign	Positive	-0.4%	Huggies “Expensive $h*t” livestream campaign for Little Snugglers protection.

Pattern Detected

Recent history shows OMC often trading flat to lower on otherwise positive corporate or recognition news, with only one clearly aligned positive reaction.

Recent Company History

Over the past month, Omnicom issued several corporate updates and recognition announcements. An earnings release schedule on Apr 28, 2026 previously coincided with a modest +1.54% move. However, news on a unified Adobe practice, top global media rankings, innovation awards, and a marketing campaign all saw small negative next-day moves (from -0.13% to -0.57%). Against that backdrop, today’s index and M&A-related announcement adds a structural change rather than an operational update.

Market Pulse Summary

This announcement outlines upcoming S&P index changes linked to Omnicom’s acquisition of Interpublic...

Analysis

This announcement outlines upcoming S&P index changes linked to Omnicom’s acquisition of Interpublic Group and related reconstitutions in the S&P 500 and S&P SmallCap 600. For Omnicom, it represents a structural milestone rather than an operational update. In context of prior news—centered on awards, capabilities, and campaigns—investors may watch deal completion, index implementation on November 28, 2025 and December 2, 2025, and subsequent capital markets activity for further signals.

Key Terms

s&p 500, s&p smallcap 600, gics sector

3 terms

s&p 500 financial

"Sandisk Set to Join S&P 500; Upwork, First Interstate..."

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.

s&p smallcap 600 financial

"S&P Dow Jones Indices will make the following changes to the S&P 500, S&P SmallCap 600:"

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.

AI-generated analysis. Not financial advice.

NEW YORK, Nov. 24, 2025 /PRNewswire/ -- S&P Dow Jones Indices will make the following changes to the S&P 500, S&P SmallCap 600: 

• S&P SmallCap 600 constituent Sandisk Corp. (NASD: SNDK) will replace The Interpublic Group of Companies Inc. (NYSE: IPG) in the S&P 500, and PTC Therapeutics Inc. (NASD: PTCT) will replace Sandisk in the S&P SmallCap 600 effective prior to the opening of trading on Friday, November 28. S&P 500 constituent Omnicom Group Inc. (NYSE: OMC) is acquiring The Interpublic Group of Companies in a deal expected to close soon, pending final conditions.
  
  
• Upwork Inc. (NASD: UPWK) will replace Premier Inc. (NASD: PINC) in the S&P SmallCap 600 effective prior to the open of trading on Friday, November 28. Patient Square Capital is acquiring Premier in a deal expected to be completed November 25, pending final closing conditions.
  
  
• First Interstate BancSystem Inc. (NASD: FIBK) will replace Hanesbrands Inc. (NYSE: HBI) in the S&P SmallCap 600 effective prior to the opening of trading on Tuesday, December 2. Gildan Activewear (TMX/NYSE: GIL) is acquiring Hanesbrands in a deal expected to be completed December 1, 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
November 28, 2025	S&P 500	Addition	Sandisk	SNDK	Information Technology
November 28, 2025	S&P 500	Deletion	Interpublic Group	IPG	Communication Services
November 28, 2025	S&P SmallCap 600	Addition	Upwork	UPWK	Industrials
November 28, 2025	S&P SmallCap 600	Addition	PTC Therapeutics	PTCT	Health Care
November 28, 2025	S&P SmallCap 600	Deletion	Sandisk	SNDK	Information Technology
November 28, 2025	S&P SmallCap 600	Deletion	Premier	PINC	Health Care
December 02, 2025	S&P SmallCap 600	Addition	First Interstate BancSystem	FIBK	Financials
December 02, 2025	S&P SmallCap 600	Deletion	Hanesbrands	HBI	Consumer Discretionary

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/sandisk-set-to-join-sp-500-upwork-first-interstate-bancsystem-ptc-therapeutics-to-join-sp-smallcap-600-302625036.html

SOURCE S&P Dow Jones Indices

FAQ

When will Sandisk (SNDK) join the S&P 500 and what is the effective date?

Sandisk (SNDK) will join the S&P 500 effective prior to the open on November 28, 2025. According to S&P Dow Jones Indices, the change is scheduled to occur before trading begins on that date.

Which companies are being added to the S&P SmallCap 600 on November 28, 2025?

Upwork (UPWK) and PTC Therapeutics (PTCT) will be added to the S&P SmallCap 600 on November 28, 2025. According to S&P Dow Jones Indices, both additions occur effective prior to the open of trading.

Why is Interpublic (IPG) being removed from the S&P 500 on November 28, 2025?

Interpublic (IPG) is being removed because it is being acquired by Omnicom, with the deal expected to close soon. According to S&P Dow Jones Indices, the pending acquisition triggers the index deletion.

When will First Interstate BancSystem (FIBK) join the S&P SmallCap 600 and why?

First Interstate BancSystem (FIBK) will join the S&P SmallCap 600 effective prior to the open on December 2, 2025. According to S&P Dow Jones Indices, the addition follows index rebalancing tied to recent corporate changes.

What happens to Hanesbrands (HBI) in the S&P SmallCap 600 after Gildan's acquisition?

Hanesbrands (HBI) will be deleted from the S&P SmallCap 600 effective December 2, 2025. According to S&P Dow Jones Indices, Gildan's expected acquisition and related corporate changes lead to the removal.