Editor’s note: This is general educational information about Australia’s substantial holding disclosure rules and the changes now scheduled for them. It is not investment advice and does not describe any particular company, security or holder. It is based on the regulatory guides and rulebooks listed at the end.
Analysis: the number is the same, the measurement is not
The headline threshold has not moved, and that is what makes the amendments easy to underestimate. The 5% line has always been about influence rather than economics, which is why it is drawn against votes. Adding deemed economic interests to the same test changes what a reader can infer from silence. Under the old measurement, a person could build economic exposure through cash-settled derivatives without necessarily acquiring a relevant interest in the underlying votes, and the register would show nothing. Once deemed economic interests count toward the same 5%, the absence of a notice starts to mean something closer to what most readers already assumed it meant.
The two business day rule is worth reading carefully as well, because it does not run from the trade. It runs from when the holder becomes aware, or ought reasonably to be aware, that a trigger has occurred. For a fund with holdings spread across associated entities and derivative positions, awareness is an operational question about internal aggregation, not a timestamp on a contract note. The tighter 9.30 am standard during a bid period replaces the ordinary two business day window for the period when control is in play.
The exchange sits downstream of all this rather than at the centre of it. ASX Listing Rule 3.17.2 requires an Australian entity to pass on beneficial ownership tracing documents it receives under Part 6C.2 when they reveal materially different information, and the rule expressly says a difference of less than 1% from a previously disclosed substantial holding is not materially different. A note to the same rule explains why the primary notices do not travel that path: the holder, not the company, is required to give a copy to ASX under section 671B(1).
For anyone tracking ownership over the next two reporting years, the practical consequence is that the record will be discontinuous. Notices lodged before 4 December 2026 measure one thing, notices lodged after it measure a broader thing, and for six months the market will see two document formats describing the same obligation. A holding that appears to jump without any purchase may simply be the first notice filed on the new basis.
What the documents say
An investor can accumulate shares in an Australian listed company without telling anyone, right up to the point where the votes attached to their holding reach 5% of the entity’s voting shares. From that moment the Corporations Act takes over. Chapter 6C requires a substantial holding notice, and the clock that starts running is measured in business days, not weeks. What is changing, and changing soon, is what has to be counted before the 5% line is reached at all.
The threshold, and what sits inside it
ASIC sets out the arithmetic in Regulatory Guide 5. A person has a substantial holding if the total votes attached to voting shares or interests in which they and their associates have relevant interests, including interests they would have but for the exceptions in section 609, plus their deemed economic interests, is 5% or more of the total votes attached to all voting shares or interests in a listed entity. Above that line, notices are required for movements above or below the threshold and for any change of 1% or more. A second, higher line sits at 20%, above which acquisitions are only permitted through certain transactions or in certain circumstances, and the general prohibition in section 606 catches an increase from a starting point above 20% and below 90% as well.
The reason the calculation is not simply a count of registered shares is the relevant interest concept. Voting power under section 610 is the votes attached to all voting shares in which the person or an associate has a relevant interest, expressed as a percentage of total votes, and ASIC notes that votes are counted even where the relevant interest arises from power or control over disposal rather than over voting. The associate concept in section 12 pulls in holdings that sit under different names.
What Chapter 6C actually asks for, and by when
Regulatory Guide 222 lists four triggers under section 671B(1): beginning to have or ceasing to have a substantial holding, holding one at the time an entity lists, a disclosable movement in an existing holding, and making a takeover bid. The deadline in the ordinary case is set out at RG 222.20. Where the entity is not the subject of a takeover bid, the notice must be given within two business days of when the substantial holder becomes aware, or ought reasonably to be aware, that one of those situations has occurred.
During a bid the clock tightens sharply. RG 222.21 requires the notice by 9.30 am on the next trading day of the relevant financial market after the holder ought reasonably to be aware of the situation, and ASIC is explicit that this applies to all substantial holders, not only the bidder. The same overnight standard applies to bidders disclosing the level of acceptances, which is why ASIC warns that a bidder should carefully monitor acceptances at the close of offers.
Netting is not permitted. Where a holding moves in one direction and then back, ASIC says the holder must disclose the movement in each direction, and must not merely disclose the net movement between one notice and the next. Where the notice is prompted by a disclosable movement, the holder must give the size and date of that movement and details of each transaction that produced it, with on-market trades on the same day in the same class able to be aggregated only if the highest and lowest per security consideration and the total consideration are disclosed.
The regime is being rewritten, with dates already fixed
The familiar paperwork is on its way out. Schedule 1 to the Treasury Laws Amendment (Strengthening Financial Systems and Other Measures) Act 2025 commences on 4 December 2026. From that date until 3 June 2027, ASIC will accept either a new Substantial Holding Notice or one of three transitional forms: Form 603 for an initial substantial holding, Form 604 for a change of interests, and Form 605 for ceasing to be a substantial holder. From 4 June 2027, substantial holding information may only be disclosed using the Substantial Holding Notice.
The substantive change sits underneath the forms. The 5% threshold is now triggered by a person’s combined relevant interests and deemed economic interests, a concept built around physically settleable and non-physically settleable derivatives and set out in the new sections 671AE to 671AQ. Offsetting short positions are counted too. A holder using a transitional form who needs to disclose a deemed economic interest or an offsetting short position must attach an annexure giving the derivative-based holding percentage, the relatable derivative-based holding percentage, the deemed physically settleable and non-physically settleable derivative-based holding percentages, the offsetting short position and its percentage.
ASIC has also carved out foreign duplication. Under section 671F, as supported by the ASIC Corporations (Listed Entities Enhanced Beneficial Ownership) Instrument 2026/482, the substantial holding requirements do not apply to an entity already subject to regimes ASIC has declared equivalent, naming the New Zealand Financial Markets Conduct Act, the FCA’s Vote Holder and Issuer Notification Rules in the United Kingdom, and the relevant subsections of section 13 of the United States Securities Exchange Act, provided the entity passes a copy to the operator of each declared market on whose official list it appears.
