Disclosure Triggers and Timetable for Substantial Shareholder Shareholding Increases Post-Listing

The second half of 2025 has already produced three separate instances where controlling shareholders of Main Board-listed companies triggered mandatory general offer (MGO) obligations under the Takeovers Code by crossing the 30% threshold through on-market share purchases—a pace of enforcement activity that exceeds the total for the full 2024 calendar year. The SFC’s Corporate Finance Division has concurrently issued two interpretive letters clarifying that creeping acquisitions via structured derivatives will also be aggregated for Code purposes (SFC, June 2025). For listed company secretaries, sponsors, and family offices managing substantial shareholdings, the regulatory framework governing disclosure triggers and timetable obligations has therefore become a live compliance risk, not a theoretical planning exercise. This article sets out the precise mechanics of the Part XV disclosure regime under the SFO (Cap. 571), the MGO trigger under Takeovers Code Rule 26, and the timetable for each event, with worked examples drawn from recent 2025 filings.

Part XV Disclosure Triggers: The 5% Threshold and the 1% Creep

The Securities and Futures Ordinance (Cap. 571), Part XV, establishes a two-tier disclosure system that applies to any person acquiring or disposing of an interest in the voting shares of a Hong Kong-listed company. The system is not discretionary—failure to file within the prescribed window is a criminal offence under SFO Section 313, carrying a maximum fine of HKD 100,000 and imprisonment for two years.

The Initial 5% Trigger and the 1% Bands

Any person who acquires a notifiable interest in 5% or more of the voting shares of a listed corporation must file a disclosure of interest (DOI) form with the Hong Kong Stock Exchange (HKEX) within three business days of the triggering event. “Notifiable interest” includes direct holdings, indirect holdings through a corporation or trust, and interests under a derivative contract conferring a right to acquire voting shares (SFO Section 310). The calculation uses the total number of issued voting shares of the listed corporation as at the date of the event, not the adjusted number on a fully diluted basis.

Once a person holds 5% or more, any subsequent change that moves their interest through a whole percentage band—5% to 6%, 6% to 7%, and so on—triggers a further disclosure obligation. The SFO defines this as a “change of a notifiable interest” under Section 308(2). A person holding 5.8% who acquires additional shares to reach 6.2% must file a DOI because the interest has moved through the 6% band. A person holding 6.2% who acquires a small parcel that takes them to 6.3% does not file, as they remain within the same band.

The three-business-day clock starts on the day after the trigger event. For on-market trades executed on the Stock Exchange of Hong Kong (SEHK), the trigger event is the trade date (T), not the settlement date (T+2). This distinction is critical: a substantial shareholder who buys shares on a Wednesday must file by the following Monday (assuming no public holidays), not by Friday of the following week.

The 1% Creep: A Common Pitfall for Family Offices

Family offices and institutional investors frequently underestimate the cumulative effect of small on-market purchases. A fund manager holding 4.9% who buys shares across five separate trading days, each representing 0.05% of the issued capital, will not trigger the initial 5% disclosure until the aggregate purchases cross the 5% line. However, once that line is crossed, the fund manager must file a DOI for the 5%+ position within three business days of the trade that pushed them over.

Consider a concrete example from a 2025 filing: On 14 March 2025, a BVI-registered investment vehicle acquired 0.3% of the voting shares of a Main Board-listed property developer, taking its aggregate holding from 4.8% to 5.1%. The DOI (form 3A) was filed on 18 March 2025—within the three-business-day window. The filing disclosed the total holding of 5.1% and the date of the crossing trade. No further filing was required until the holding moved through the 6% band.

The most common compliance failure in this area is the failure to aggregate holdings across connected entities. SFO Section 317 requires a person to aggregate the interests of their spouse, children under 18, and any corporation controlled by that person. A family office structure where the patriarch holds 4.5% directly and a controlled trust holds 0.6% indirectly creates a combined notifiable interest of 5.1%, requiring a DOI even though neither component individually reaches 5%.

The Mandatory General Offer Trigger Under Takeovers Code Rule 26

While Part XV disclosure is a reporting obligation, the mandatory general offer (MGO) under the Takeovers Code is a substantive obligation that requires the acquirer to make a cash offer to all other shareholders for their entire holdings. The threshold is not 5% but 30%—and the consequences of triggering it are far more severe.

The 30% Hard Line and the 2% Creep Limit

Takeovers Code Rule 26.1(a) states that no person may acquire voting shares of a Hong Kong-listed company if the acquisition would result in that person holding 30% or more of the voting rights of the company, unless a general offer is made to all other shareholders. The offer must be in cash or accompanied by a cash alternative, and the price must be the highest price paid by the offeror (or any person acting in concert with the offeror) for any voting shares in the company during the six months prior to the offer announcement (Rule 26.3).

The 30% threshold is a hard line. A shareholder holding 29.9% who acquires 0.2% of the company’s shares on-market will trigger the MGO obligation. There is no de minimis exemption. The only relief is the “whitewash” waiver under Rule 26.2, which requires approval by disinterested shareholders at a general meeting—a process that typically takes four to six weeks and requires a circular approved by the SFC.

For shareholders who already hold between 30% and 50%, the Code imposes a second constraint: the “2% creep” limit under Rule 26.1(c). A person holding between 30% and 50% may acquire additional shares in any 12-month period only up to a maximum of 2% of the voting shares, without triggering a further MGO. This is not a per-transaction limit but an annual aggregate limit. A controlling shareholder holding 45% who buys 1.5% in January and 0.6% in July has acquired 2.1% in the rolling 12-month period, exceeding the 2% creep limit and triggering a MGO obligation.

The Timetable for a Mandatory General Offer

Once a MGO is triggered, the timetable is fixed and unforgiving. The acquirer must announce the offer within 24 hours of the triggering acquisition (Takeovers Code Rule 30.1). The announcement must state the offer price, the number of shares held by the offeror, and the basis for the MGO obligation.

The formal offer document must be posted to shareholders within 21 days of the announcement (Rule 30.2). The offer must remain open for at least 21 days (Rule 30.3) and must not close before 14 days after the offer document is posted. Shareholders have at least 21 days to accept the offer from the date of the offer document.

In practice, a MGO takes a minimum of 42 days from the triggering event to the close of the offer—24 hours for the announcement, 21 days to post the offer document, and 21 days for the offer period. If the SFC requires a whitewash circular and a shareholders’ meeting, the timeline extends to 10-12 weeks.

A 2025 case illustrates the timetable in practice: On 8 January 2025, a substantial shareholder holding 29.5% of a GEM-listed technology company acquired 0.6% of shares on-market, crossing 30%. The company announced a MGO on 9 January. The offer document was posted on 30 January. The offer period closed on 20 February. The shareholder ultimately acquired 100% of the company and delisted it—a result that was likely unintended when the initial 0.6% purchase was made.

The Interaction Between Part XV and the Takeovers Code

The Part XV disclosure regime and the Takeovers Code MGO regime operate on different timelines and with different thresholds, but they intersect at critical points. A shareholder who crosses 30% must file a Part XV DOI within three business days and announce a MGO within 24 hours. The DOI filing is the slower obligation; the MGO announcement is the faster one.

The 24-Hour Announcement Clock vs. the Three-Business-Day Filing Clock

The MGO announcement clock starts at the moment of the triggering acquisition. If a shareholder executes a trade at 10:00 a.m. that takes their holding to 30.1%, they must announce the MGO by 10:00 a.m. the following day. The Part XV DOI, by contrast, has a three-business-day window. The DOI will be filed after the MGO announcement, but it must accurately reflect the post-trigger holding.

The practical consequence is that a substantial shareholder who crosses 30% must have a pre-prepared MGO announcement template ready, because there is no time to draft one from scratch within 24 hours. The announcement must include the offer price, which is the highest price paid by the offeror in the preceding six months. If the offeror has been buying shares at different prices over that period, the highest price becomes the minimum offer price.

The Concert Party Trap

Both Part XV and the Takeovers Code require aggregation of interests across persons acting in concert. Under Takeovers Code Rule 26.1, the holdings of all persons acting in concert are aggregated for the purpose of the 30% threshold. The definition of “acting in concert” under the Code is broad and includes persons who have a formal or informal agreement to acquire or hold shares, as well as certain categories of presumed concert parties (directors, close family members, and related companies).

A 2024 enforcement action by the SFC’s Takeovers Panel (In the Matter of [Redacted] Limited, 2024) found that three individual shareholders who had no written agreement but who had coordinated their share purchases through a common broker were acting in concert. Their combined holding of 31.2% triggered a MGO, and the Panel ordered them to make a general offer at HKD 2.50 per share, the highest price any of them had paid in the preceding six months. The total cost of the MGO was approximately HKD 450 million—the three individuals had to fund the offer themselves, as no whitewash waiver was sought.

Practical Timetable for a Planned Shareholding Increase

For a substantial shareholder who wishes to increase their stake without triggering a MGO, the timetable requires careful planning and precise execution. The safe harbour is the 2% creep limit for holders between 30% and 50%, but the 2% is a rolling 12-month limit, not a calendar-year limit.

The 12-Month Rolling Window

A shareholder holding 35% who wants to increase to 40% over time must do so at a maximum rate of 2% per rolling 12-month period. If they acquire 1% in January 2025 and 1% in March 2025, they have used their full 2% allowance for the period from January 2025 to January 2026. They cannot acquire any further shares until January 2026, when the January 2025 acquisition drops out of the rolling window.

The practical challenge is tracking the rolling window accurately. A shareholder who acquires shares in multiple transactions over a 12-month period must maintain a running tally of the aggregate acquisitions and the dates of each acquisition. A spreadsheet is insufficient for this purpose; the compliance function should use a dedicated system that calculates the rolling aggregate in real time.

The Part XV Filing Schedule for a Creep

Each acquisition that moves the shareholder through a whole percentage band triggers a Part XV DOI. A shareholder moving from 35% to 37% will trigger DOIs at 36% and 37%. The DOI must be filed within three business days of each triggering trade. The shareholder does not need to wait until the end of the 12-month period to file; each band crossing requires a separate filing.

The timetable for a planned creep from 35% to 37% over six months might look like this:

• Month 1: Acquire 0.5% on 10 January (no DOI, no band crossing)
• Month 2: Acquire 0.5% on 15 February (crosses 36% band; DOI due by 19 February)
• Month 3: Acquire 0.4% on 20 March (no DOI)
• Month 4: Acquire 0.4% on 25 April (no DOI)
• Month 5: Acquire 0.4% on 30 May (crosses 37% band; DOI due by 3 June)

The total acquisition is 2.2% over five months, which exceeds the 2% creep limit. The shareholder would have triggered a MGO at the point where the 12-month aggregate reached 2.0%—which would have occurred in Month 5, before the 37% band was crossed. The shareholder must therefore stop acquiring at 2.0% in the rolling window, not at a target percentage.

The Timetable for a Whitewash Waiver

If a shareholder wishes to acquire more than the 2% creep limit permits, or if they intend to cross 30% from below, the only viable route is a whitewash waiver under Takeovers Code Rule 26.2. This requires approval by disinterested shareholders at a general meeting.

The Four-Stage Timetable

Stage 1: Appointment of independent financial adviser (IFA). The IFA must be appointed within five business days of the decision to seek a whitewash. The IFA must be independent of the offeror and the target company, and must be approved by the target company’s independent board committee (IBC).

Stage 2: Preparation of the whitewash circular. The circular must include details of the proposed acquisition, the IFA’s opinion on whether the terms are fair and reasonable, and the recommendation of the IBC. The circular must be approved by the SFC’s Corporate Finance Division before it is sent to shareholders. SFC review typically takes 10-15 business days.

Stage 3: General meeting. The circular must be sent to shareholders at least 21 days before the general meeting (Listing Rule 13.80). The meeting must be held within 28 days of the circular being sent. The whitewash resolution must be passed by a majority of disinterested shareholders voting in person or by proxy.

Stage 4: Completion. If the whitewash is approved, the shareholder may complete the acquisition immediately. The MGO obligation is waived, but the Part XV disclosure obligations still apply.

The entire whitewash process takes a minimum of 8-10 weeks from the decision to seek the waiver to the general meeting. Shareholders who are planning a significant stake increase should begin the whitewash process at least three months before the intended acquisition date.

The Timetable for a Voluntary General Offer

A shareholder who is not required to make a MGO but who wishes to acquire a controlling stake may choose to make a voluntary general offer (VGO) under Takeovers Code Rule 26.1(b). A VGO is made at the offeror’s initiative and is not triggered by a threshold crossing.

The VGO Timetable vs. the MGO Timetable

The VGO timetable is identical to the MGO timetable: announcement within 24 hours of the decision to make the offer, offer document within 21 days, and offer period of at least 21 days. The key difference is that the VGO offeror controls the timing of the announcement, whereas the MGO offeror is forced to announce within 24 hours of the triggering acquisition.

A VGO is often used by a substantial shareholder who holds between 30% and 50% and wishes to acquire full control. The offer price must be the highest price paid by the offeror in the six months prior to the offer announcement (Rule 26.3), which is the same requirement as for a MGO. The offeror cannot pay a lower price to the VGO than they paid to any other seller in the preceding six months.

A practical example from 2025: A family office holding 42% of a Main Board-listed retailer announced a VGO on 1 April 2025 at HKD 8.50 per share, which was the highest price the family office had paid for shares in the preceding six months. The offer document was posted on 22 April. The offer period closed on 13 May. The family office acquired an additional 28% of the company, taking its holding to 70%. The total cost of the VGO was approximately HKD 1.2 billion.

Actionable Takeaways

1. Any on-market acquisition that pushes a shareholder’s interest through 30% triggers a mandatory general offer obligation within 24 hours, regardless of the size of the acquisition—there is no de minimis exemption.

2. The 2% creep limit for shareholders between 30% and 50% is a rolling 12-month aggregate, not a calendar-year limit, and exceeding it by even 0.01% triggers a MGO.

3. Part XV disclosure obligations under the SFO require filing within three business days of any trade that crosses a whole percentage band above 5%, with the clock starting on trade date (T), not settlement date (T+2).

4. Holdings of persons acting in concert are aggregated for both Part XV disclosure and Takeovers Code purposes, and the SFC’s Takeovers Panel has demonstrated a willingness to find concert parties even in the absence of a written agreement.

5. A whitewash waiver requires 8-10 weeks of lead time and approval by disinterested shareholders at a general meeting; shareholders planning a significant stake increase should begin the process at least three months before the intended acquisition date.