Euronext Set To Join CAC 40 As It Moves To Acquire Athens Stock Exchange

Euronext will be admitted to France’s benchmark CAC 40® index later than market close on Friday, 19 September, with inclusion effective Monday, 22 September 2025. The elevation caps more than a decade of expansion since the group’s 2014 IPO, when its market capitalisation stood at €1.4 billion; as of 22 August 2025 it had reached €14.5 billion, underpinned by a tripling of revenue and a fourfold increase in adjusted EBITDA over the period.

From an operator of four venues at listing, Euronext now runs regulated markets in Amsterdam, Brussels, Dublin, Lisbon, Milan, Oslo and Paris, and has signalled plans to add Athens to its federal model. The group attributes performance to strategic acquisitions, geographic expansion, and diversification into trading, clearing, settlement, custody and issuer services.

“We have accelerated our growth through strategic acquisitions, geographic expansion, and diversification into new asset classes, trading and post-trade services, and SaaS answers,” said Stéphane Boujnah, CEO and Chairman of the Managing Board. “This milestone illustrates the resilience of our business model and Euronext’s pivotal role in the financial ecosystem.”

Bid To Integrate Greece Into The Federal Model

Alongside the index elevation, Euronext has submitted a voluntary share platform offer for HELLENIC platformS–ATHENS STOCK platform S.A. (ATHEX). The proposed fixed conversion rate is 20 ATHEX ordinary shares for each new Euronext share, valuing ATHEX at approximately €412.8 million based on Euronext’s 30 July closing price and implying a circa 27% premium to ATHEX’s three-month undisturbed VWAP as of 30 June. The ATHEX board unanimously supports the offer and has entered into a cooperation agreement.

The transaction would bring Greek , aligning listings, trading and post-trade on Euronext’s unified technology stack. Euronext targets €12 million of annual run-rate cash synergies by 2028, primarily from migration to the Optiq® trading platform and the harmonisation of central functions, with expected implementation costs of €25 million. The deal is expected to be accretive later than the first year of synergy delivery.

Why Greece, Why Now

ATHEX operates across , clearing, settlement and custody, and owns a stake in the Greek power platform EnEx. As of H1 2025, about 49% of ATHEX revenue derived from CSD and clearing activities. The Greek improving macro indicators and rising international confidence; ATHEX net revenue in 2024 increased 76% versus 2020, with EBITDA tripling over the identical period.

“Greece has experienced strong economic growth in recent years,” Boujnah said. “Joining Euronext’s best-in-class trading and post-trade technology will boost the visibility and attractiveness of the Greek markets at an international scale.”

Governance, Oversight And Timeline

Consistent with Euronext’s federal governance, Greece would gain representation at group level: an independent figure from the Greek financial ecosystem would be proposed for the Supervisory Board at the 2026 AGM, and the ATHEX CEO would be proposed to join Euronext’s Managing Board. The Hellenic Capital Markets Commission would join Euronext’s College of Regulators on a pari passu basis with other European supervisors.

The offer is subject to customary approvals and a minimum acceptance condition of 67% of ATHEX voting share capital (with Euronext reserving the right to amend in accordance with Greek law). Subject to clearance, the offer period is expected to open in Q4 2025, with completion targeted by year-end.

Strategic Context: From National Bourses To A Pan-European Stack

Euronext’s expansion has emphasised common technology and post-trade integration. Following prior migrations (Dublin, Oslo Børs, Borsa Italiana) to Optiq® and the rollout of Euronext Clearing across seven markets, the group cites improved liquidity and market quality metrics. Extending this model to Greece would reduce post-trade fragmentation further and position Athens as a .

For ATHEX shareholders, the all-share structure allows continued participation in a larger, more diversified group with exposure to over 1,800 listed companies and a combined market capitalisation above €6 trillion. For Euronext investors, management reiterates return hurdles (ROCE > WACC in years 3–5) and maintains headroom for additional diversification transactions.

Outlook

Index inclusion typically broadens the investor base via benchmark-tracking inflows, while the ATHEX combination—if completed—would extend Euronext’s geographic reach and deepen its post-trade footprint. Together, the moves align with the group’s ambition to serve as the backbone of Europe’s , leveraging scale, harmonised technology, and a multi-jurisdiction regulatory framework.

“Our inclusion in the CAC 40 and our expansion to Athens both demonstrate the resilience of our business model and our pivotal role in shaping European capital markets,” Boujnah said. “This is not just recognition of what we have achieved, but also a platform for the next decade of growth.”