Mediobanca's Surpassing 70% MPS/OPAS Adherence: A Catalyst for Strategic Investor Reevaluation?

The recent acquisition of Mediobanca by Monte dei Paschi di Siena (MPS) through a public purchase and exchange offer (OPAS) has reshaped Italy's banking landscape. As of September 2025, the adherence rate for the OPAS stood at 62.29%, surpassing the critical 50%+1 share threshold required for controlMps gains control of Mediobanca: Opas closes at 62.29%^[1]. While this figure fell short of the 70% mark often cited as a benchmark for full institutional consolidation, the strategic implications of this acquisition—particularly for shareholder value and institutional ownership dynamics—demand closer scrutiny.

Adherence Rate Progression and Strategic Thresholds

The OPAS, launched in July 2025, initially secured 38.5% adherence by September 3, exceeding the 35% minimum thresholdMPS offer for Mediobanca hits minimum take-up threshold^[2]. By September 9, the rate had surged to 62.29%, enabling MPS to gain de facto controlMediobanca GM says Monte dei Paschi to reach 80% ownership^[3]. A subsequent reopening period (September 16–22) allowed remaining shareholders to participate, though final data on post-reopening adherence remains pendingMps confirms reopening of terms of Opas on Mediobanca for 5 days^[4]. While 62.29% is below the 70% threshold often associated with full institutional buy-in, it is sufficient for MPS to consolidate control and initiate integration.

The offer's structure—a mix of €0.90 in cash and 2.533 MPS shares per Mediobanca share—was pivotal in securing this level of adherenceMPS relaunches bid for Mediobanca with €13.5bn partial-cash offer^[5]. This hybrid approach not only addressed shareholder concerns about liquidity but also leveraged MPS's deferred tax assets (DTAs), estimated at €13 billion, to enhance the combined entity's balance sheetPaschi Takes Over Mediobanca to Transform Italian Banking^[6].

Institutional Ownership Shifts and Strategic Resilience

The acquisition has triggered a seismic shift in Mediobanca's ownership structure. Key institutional stakeholders, including DELFIN S.à r.l. (19.812%) and GRUPPO F.G. CALTAGIRONE (7.391%), fully subscribed to the offer, aligning with MPS's vision for a unified Italian banking giantShareholders - Mediobanca Group^[7]. This consolidation reduces the influence of dispersed retail shareholders and centralizes decision-making under MPS's governance framework.

Such institutional alignment signals strategic resilience. By securing control through a majority stake, MPS can now pursue a merger with Mediobanca, creating Italy's third-largest lender by assetsBanks in turmoil, Mps and Mediobanca fly after successful Opas^[8]. This move is expected to unlock synergies in wealth management, private banking, and investment banking, with combined revenue potential exceeding €20 billion annuallyWhat will be the future of Mediobanca after the takeover of MPS?^[9]. However, challenges remain, including the integration of Mediobanca's elite investment banking capabilities with MPS's retail-focused operations and the retention of key talent.

Shareholder Value Realization: A Double-Edged Sword?

Mediobanca's pre-takeover shareholder value strategy—pledging €4.9 billion in dividends and buybacks by 2028—was designed to resist the MPS bidMediobanca targets €4.9bn shareholder payout, eyes strong profit and revenue growth^[10]. While this plan remains on the books, the acquisition complicates its execution. Post-takeover, the focus shifts to leveraging synergies rather than standalone payouts. For instance, access to Mediobanca's DTAs could reduce MPS's tax liabilities, potentially freeing capital for reinvestment or shareholder returnsMps gains control of Mediobanca: Opas closes at 62.29%^[11].

Yet, the takeover also raises questions about value destruction. Mediobanca's leadership previously warned that the bid would “strongly destroy” value due to integration costs and operational redundanciesMediobanca GM says Monte dei Paschi to reach 80% ownership^[12]. However, MPS's revised offer—adding €750 million in cash and lowering the validity threshold—suggests a calculated effort to mitigate these risksMPS relaunches bid for Mediobanca with €13.5bn partial-cash offer^[13].

Regulatory and Market Implications

Regulatory scrutiny remains a wildcard. The European Central Bank (ECB) and Italy's Consob are monitoring the merger's impact on competition and financial stabilityFour priorities to drive financial institutions’ focus in 2025^[14]. Additionally, the combined entity's ownership of Assicurazioni Generali shares could trigger mandatory takeover rules, further complicating the integration processWhat will be the future of Mediobanca after the takeover of MPS?^[15].

From a market perspective, the stock performance of both MPS and Mediobanca has been volatile. Post-OPAS, MPS shares surged on optimism about synergies, while Mediobanca's stock traded at a premium to its pre-bid levelsBanca Monte dei Paschi di Siena surges as Mediobanca takeover gains traction with 62% tendered^[16]. However, long-term performance will depend on the success of integration and the ability to capitalize on cross-selling opportunities.

Conclusion: A Catalyst for Reevaluation

While Mediobanca's adherence rate did not surpass 70%, the 62.29% threshold achieved by MPS is sufficient to drive strategic reevaluation. The acquisition underscores the growing trend of institutional consolidation in European banking, where control is increasingly concentrated among a few dominant players. For investors, the key takeaways are:
1. Strategic Resilience: The merger positions Italy's banking sector to compete globally, though integration risks persist.
2. Shareholder Value: Short-term gains from DTAs and synergies may offset long-term integration costs.
3. Institutional Dynamics: The shift to concentrated ownership highlights the importance of governance structures in value creation.

As the dust settles on this landmark deal, investors must weigh the potential for a stronger, more diversified Italian banking giant against the challenges of integration and regulatory oversight. The final adherence rate post-reopening and subsequent institutional moves will be critical indicators of the transaction's long-term success.