Rio Tinto-Glencore Merger Talks Trigger UK Disclosure Rules amid Coal & Structure Uncertainty

Analysis of Glencore-Rio Talks and Disclosure Implications

The current Glencore-Rio Tinto discussions represent one of the most significant M&A events globally, given the sheer scale—potentially over US$200-260+ billion—and span of jurisdictions involved. While the negotiations are preliminary, they have triggered formal disclosure obligations under UK takeover law (City Code), raising strategic, regulatory, and governance questions for both companies and their shareholders.

Key Legal Obligations and Precedents: Under Rule 2.6(a) of the UK City Code, once discussions reach a ‘preliminary’ stage, the acquiring party (Rio) has until 5pm on February 5, 2026 to either announce a firm intention to make an offer or confirm it will not. This requirement secures investors’ rights to clarity and helps avoid prolonged information vacuum. The companies’ statements expressly note that these talks do not yet represent a firm offer under Rule 2.7.

Market Sensitivity & Director Disclosure Strategy: The disclosures made so far indicate that both Rio and Glencore are navigating between maintaining confidentiality and satisfying legal/regulatory disclosure obligations. The statements clarify that the discussion is a possible combination, not a firm offer, and that terms are not agreed—protecting both from actionable misrepresentation. These signals also serve to manage market expectations, reduce rumors, and guard against accusations of misleading or incomplete disclosure.

Australian Comparables: Lessons from BlueScope & Humm: In Australia, similar issues come up in cross-border and domestic takeover approaches. BlueScope, for example, received an unsolicited, non-binding and indicative proposal on December 12, 2025, from Steel Dynamics / SGH, which was kept confidential until media reveal, consistent with ASX guidance that non-binding and insufficiently definite negotiations need not be disclosed immediately. Meanwhile Humm’s case opens scrutiny around timing of disclosure and insider share trades by major shareholders, raising governance and fairness concerns.

Regulatory Trends & ASX Disclosure Expectations: ASX’s recent updates, including its guidance on naming counterparties and on the so-called ‘‘close review procedure”, suggest increasing pressure on listed entities to err on the side of disclosure when negotiations reach a certain maturity or when leaks or market rumours force the issue. Discretions remain, but failure to adequately explain or manage timing can lead to regulatory censure or shareholder unrest.

Strategic Implications: For Rio Tinto: Any bid or attempt must reconcile its existing commitments (e.g. its posture on coal), and anticipate investor and regulatory pushback. Glencore’s coal and trading operations are likely to be scrutinized severely by Rio’s ESG-sensitive shareholders. For Glencore: the value proposition in negotiation may depend heavily on how assets (especially coal) are dealt with—whether spun out, retained, or sold off. For both: the inherent complexity of scheme of arrangement approvals across UK, South Africa, Australia, and other jurisdictions may impose delay, risk, or required concessions.

Open Questions:

• Will Rio Tinto include Glencore’s coal and trading businesses, or will those parts be excluded or divested post-deal?
• Can the companies preserve commercial confidentiality through February 5 without leaks undermining their strategic negotiation leverage?
• How will regulatory bodies in Australia, South Africa, and other jurisdictions assess any competition, environmental, or foreign ownership concerns?
• What behaviour will shareholders exhibit, especially if the indicative bargain is seen as opportunistic or undervalued?

Conclusion: The Glencore-Rio scenario underlines the central tension in modern M&A disclosure: striking the balance between legitimate confidentiality in negotiations and legal obligations of transparency anchored in jurisdictional takeover codes and continuous disclosure regimes. For boards and executives, this means being prepared to comply rigorously with formal deadlines, managing market communication proactively, and considering how evolving regulatory expectations may shift long-standing norms around when, and what parts of, negotiations must be made public.