The Strategic Narrative when Present in a B3 Index

With the new compositions disclosed for the main B3 indexes — valid for a four-month period, from May to August 2025, a theme that goes far beyond simple technical analysis or institutional curiosity is reinforced: being (or not) part of an index has profound implications on the visibility, capital flow and cost of capital of listed companies. 

Understanding and acting strategically around these events is more than just a technical obligation for IR professionals, it’s an opportunity to reinforce the corporate narrative, increase sell-side engagement and positively influence the market’s risk perception.

Considering this, MZ,

who is constantly seeking to empower IR professionals by offering cutting-edge technology, exceptional customer service, and disseminating relevant content, released its Updated Study for B3 Index Portfolios, from May to August 2025, containing a comprehensive overview of portfolio changes for the main indexes of the Brazilian stock exchange, namely IBOVESPA, IBrX100, MLCX, SMLL, IDIV, ISE, IGPTW, IDIVERSA and IFIX. The data, in addition to being informative, provides valuable insights into IR’s strategic performance, especially when the search for narrative is a differentiating and valuable element for attracting and retaining investors.

What Changes in the Portfolios from May to August 2025?

MZ’s study brings relevant highlights. The IBOVESPA index, for example, included Direcional (B3: DIRR3) and SmartFit (B3: SMFT3)  and the companies in the Novo Mercado segment represent 65.6% of the total index, with highlight to companies from the Electric Energy sector, accounting for 13.8%. The IBrX100 index now includes EcoRodovias (B3: ECOR3), , which appreciated more than 55% in the year. The MLCX index which included Carrefour (B3: CRFB3) –  even if for a short period, had a performance of 11.2% in the year. 

The SMLL index, a small cap index, had significant changes with 4 new companies entering, totaling 115 companies in the index, and the Retail sector accounts for 16.5% of the total. 

All the companies in the IDIV index, which focuses on dividend payers, had share appreciation in the year, with highlight to Plano & Plano (B3: PLPL3), recording a 41% increase in 2025. The new companies in the ISE (Corporate Sustainability Index) recorded a consistent appreciation in share price, and Sabesp (B3: SBSP3) stood out as having one of the highest average trading volumes in the index.

These data are not mere statistics: they construct the backdrop for allocation decisions by institutional investors and passive funds, in addition to being a thermometer for the attractiveness and consistency of the capital strategy of these companies.

Why Does Being Part of an Index Matter?

The inclusion (or exclusion) of a company in indexes, such as the IBOVESPA or SMLL, does not just translate into headlines. It directly impacts capital flows, since many passive funds (ETFs and index funds) are required to adjust their portfolios according to changes made to the composition of the indexes. For active managers, the presence of a company in a certain index serves as a sign of liquidity, governance and appeal.

This is directly reflected in changes to the company’s cost of capital. Companies that are part of an index tend to have higher liquidity, greater analyst coverage, and easier access to new debt or equity instruments at more favorable rates. On the other hand, companies that are excluded from an index may see their investor base dwindle, their narrative weaken and their perceived market risk — in which market agents end up demanding greater returns.

The Relevance of Investor Relations Professionals

Within this context, IR professionals gain a prominent role. They are responsible for translating the company’s accounting and strategic facts into narratives that are understandable, credible and attractive to the market. Being included in an index is not just an operational fact, but a reputational asset that can (and should) be explored in the company’s communication with investors.

A strategic IR should:

• Continuously monitor the index’s composition rules;
• Anticipate entry or exit scenarios;
• Proactively communicate these changes to the market, explaining their impacts and context;
• Coordinate with internal areas so they provide necessary data that reinforce the eligibility pillars (governance, liquidity, sustainability, etc.);
• Take advantage of being part of an index as valuable argument in roadshows, earnings releases, investor days and institutional presentations.
• When the company joins indexes such as ISE or IDIVERSA, IR professionals  have the opportunity to integrate the index’s ESG agenda into the company’s financial narrative, demonstrating how sustainability and performance can go hand in hand — a powerful argument for reducing cost of capital, especially with institutional investors.

In particular, when it comes to indices such as the ISE or IDIVERSA, IR has the opportunity to integrate the ESG agenda into the financial narrative, demonstrating how sustainability and performance can go hand in hand – a powerful argument in reducing the cost of capital, especially with institutional investors.

Narrative, Transparency and Reducing the Cost of Capital

Several academic and empirical studies have already demonstrated that preciseness, consistency and transparency in communication with the market can influence a company’s risk perception, value and, consequently, cost of capital. Companies that proactively build their image and narrative — particularly when they reinforce their presence in relevant indexes — tend to benefit from smaller spreads, greater analyst coverage and easier access to capital.

The MZ Study itself shows that most companies who joined indexes in 2025 had share price appreciation in the previous months, indicating a correlation between good performance, visibility and inclusion into indexes. More than that, this appreciation was reinforced after the new portfolios were announced while funds need to adjust their positions and the market responds with optimism to the entries.

This is a virtuous cycle that IR professionals must learn to explore: performance leads to inclusion, which leads to more flow, which leads to better risk assessment, which leads to lower cost of capital — as long as it is properly communicated.

Practical Cases of Strategic Communication

Imagine a company that has just joined the IDIV index. IR professionals can (and must):

• Prepare a release highlighting the company’s entrance and explaining what the index represents;
• Share a post on the institutional LinkedIn with data on dividends paid in recent years;
• Make a video with the CFO commenting on the importance of dividend distribution for the company’s capital strategy;
• Update the ESG and governance section of the IR website, mentioning the index.
• These simple actions reinforce the value narrative and demonstrate alignment with the market, all of which directly contribute to attracting long-term investors and improving risk perception.

On the other hand, if a company is excluded from an index, IR professionals should not hide this fact. It is possible to contextualize the exit (for reasons such as changes in methodology, for instance), and signals that recovery efforts are being made, above all, reinforcing that the company’s long-term pillars remain solid. Transparency is even more valuable during these times, and an active IR team makes all the difference in softening short-term impacts and ensuring long-term returns.

Conclusion

The analysis of the new portfolios for B3 indexes, as presented in the MZ study, shows that indexes, far beyond their numbers and trading codes, function as true mirrors of what the market values​at any given moment: liquidity, governance, sustainability, performance or dividends.

For companies, being present in these indexes is a clear sign of credibility and attractiveness. But to reap the rewards of being in an index, whether in terms of gaining liquidity, visibility, analyst coverage or reducing cost of capital, the Investor Relations area must be active, strategic, and well-prepared.

IR professionals need to go beyond the role of translating results: they must act as narrative curators, perception architects and institutional ambassadors for the company. These professionals help transform facts into value — and, within this context, indexes create opportunities that must not be dismissed.

We hope to have assisted by bringing information on this Study, which we consider very important for companies and the IR ecosystem. To learn more, click here and access the Study page. If you have any questions, we are always here at your service!

External Communications and MZ Research Team

Cássio Rufino
CFO & COO

Media Relations
imprensa@mzgroup.com | (11) 94242-5988

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About MZ

MZ (www.mzgroup.com.br) is the largest and leading independent global player in investor relations (IR) solutions.

Founded in 1999, the Company has surpassed the mark of 2,000 websites published, currently serving over 800 companies and investment management firms listed on 12 stock exchanges.

To empower IR strategies, MZ delivers innovative technologies and exceptional customer service, ensuring long-term partnerships.