Introduction

Stewardship and governance literature often treats engagement as a single discipline, but recent live cases demonstrate that it operates through diverse theories of change. This report examines three distinct models of investor-driven corporate change from the past twenty-four months: a coalition-led shareholder resolution at BP, a bilateral confrontation at Honeywell, and a quiet boardroom campaign at Bâloise. Each model requires different capabilities and produces varied outcomes. The document provides a working typology for investment professionals to calibrate engagement levers and for corporate boards to prepare for activist pressure expected in 2026 and 2027.

Case one: ACCR at BP — coalition resolution

In January 2026, the Australasian Centre for Corporate Responsibility (ACCR) filed Resolution 24 at BP’s AGM, backed by six institutional investors representing £191bn in assets under management. The filing followed a period of engagement beginning in 2022 and focused on capital discipline. Specifically, the supporting case highlighted that BP’s gas assets were more expensive than 76% of global pre-final investment decision supply and exploration capital expenditure was 20% above the decade’s annual average. The subsequent vote on 23 April 2026 saw 25.85% support, the highest ever for a management-opposed resolution at BP.

The campaign forced the board into a mandatory consultation under the UK Corporate Governance Code. Following the AGM, new CEO Meg O’Neill emphasised “balance sheet” and capital discipline during earnings calls. While BP’s share price rose 33% over the period, much of this was attributed to crude oil price increases. However, the campaign successfully reframed management messaging and established a governance milestone. This approach is deemed effective for large, regulated companies where individual shareholder leverage is small, though it is noted as being slow and procedurally expensive.

Case two: Elliott at Honeywell — bilateral confrontation

Elliott Management disclosed a stake exceeding US$5bn in Honeywell in November 2024, arguing that the conglomerate structure masked value. Using a sum-of-the-parts arithmetic, Elliott projected 51-75% upside by separating Aerospace and Automation units. Within 86 days, the Honeywell board announced a three-way break-up, including the previously announced Advanced Materials spin-off (Solstice Advanced Materials or SOLS). SOLS was spun off in October 2025, and the Aerospace Technologies separation was scheduled for June 2026.

This case demonstrates how a single activist with sufficient capital and a clear underwriting argument can force strategic change without an AGM resolution or proxy fight. Although Elliott remained approximately flat against its entry price over 18 months, underperforming the S&P 500, it successfully rewrote the corporate structure of a US$150bn-cap industrial giant. The message for corporates is that boards should not wait for a proxy fight; they must be prepared to explain why a portfolio is worth more together than apart.

Case three: Cevian at Bâloise — quiet constructive activism

Cevian Capital utilised a “constructive activist” model at Swiss insurer Bâloise, building a 9.4% stake by September 2024. This campaign was facilitated by a structural governance change in April 2024, which removed a 2% voting-rights cap and lowered the threshold for a qualified majority. Cevian initially pressed privately for the divestment of non-core units to refocus on the Swiss core. When management’s response was deemed underwhelming, Cevian escalated by nominating a partner for election to the board.

The pressure catalysed an all-share merger between Bâloise and Helvetia in April 2025, creating a combined entity worth over CHF 18bn. Cevian exited its position shortly after, achieving a return of approximately 33% in under twelve months. This case illustrates that an activist building a large position quietly can become a decisive constraint on a board’s freedom of action by accumulating a blocking position, even without public letters or proxy fights.

Synthesis

Every successful engagement is built on a company-specific underlying thesis, ranging from capital allocation to sum-of-the-parts arithmetic or operational restructuring. Values-led language alone is insufficient to move capital; financial-materiality framing is now the primary survivor across mandates due to the political environment and regulatory frameworks. The report highlights that outcomes are not uniform: some achieve structural transformation while others gain governance concessions. Investors are cautioned not to score engagement on binary “pass/fail” metrics for resolutions, as shareholder dissent usually builds slowly across various vote items.

Structural shifts

Three major shifts have occurred over the last twenty-four months. First, the “Big Three” stewardship monolith (BlackRock, Vanguard, State Street) has fractured, with firms splitting stewardship functions and voting policies. Second, the SEC has narrowed the definition of “passive” status for 5%+ shareholders, potentially chilling large-shareholder engagement in the US. Conversely, the EU framework continues to push for active engagement. Third, there is an increasing reliance on “withhold” campaigns rather than full proxy fights, as they are cheaper and often sufficient to trigger leadership changes.

Key takeaways

There is no single best practice for engagement; the approach must fit the specific company and situation. Financial materiality is the only frame that survives current political crossfire. For issuers, the strongest defence is maintained through year-round engagement with investment and governance teams, stress-testing strategic alternatives before external pressure builds. Boards that ignore politely raised concerns from long-only shareholders risk facing more expensive and aggressive activist interventions later.

Conclusion

The three campaigns studied—ranging from a public question to a structural break-up and a quiet merger—each represent “best practice” within their specific contexts. Success looks different in each frame. The goal of studying these models is to recognise which approach a company might invite and to be prepared for the consequences of that engagement.