Japan's 5% rule, explained

Written 3 September 2026 · All explainers

How to read the markers. [D] — verified from a source retrieved for this note, listed under Sources. [I] — industry-understood; not formally disclosed by a named party. [S] — our own inference or judgment. Every figure is either sourced or marked as an estimate.

The short version

Japan’s large shareholding report (大量保有報告書, tairyō hoyū hōkokusho) is the filing a holder must make once it owns more than 5% of a listed company’s shares. Japan’s Financial Instruments and Exchange Act (FIEA) requires it within five business days, and requires a further change report every time the holding then moves by one percentage point or more. Every filing is posted, in Japanese, on EDINET — the Financial Services Agency’s free public disclosure database — as soon as it is submitted. [D — see Sources]

More than 10,000 of these filings appear each year. [D — Daiwa Institute of Research] Most foreign investors never read them: they are in Japanese, in a fixed form, and the headline number alone says little. A 5.2% stake is not, by itself, information.

The signal is the sequence of change reports, not the level — and the “purpose of holding” line tells you whose sequence to watch. A bank, broker or index manager files under a relaxed regime that hides its day-to-day moves, so its 5.2% is noise. An investor that declares an intent to make a “material proposal” cannot use that regime, so every one-point step it takes is public within five business days. That is the feed’s real content.

Two things changed on 1 May 2026, when the 2024 amendment to the FIEA took effect. Institutional investors can now coordinate votes on specific resolutions without being aggregated as “joint holders”, and cash-settled equity swaps now count towards the 5% when held with an intent to acquire or to influence. On the same day the mandatory tender-offer trigger fell from one-third to 30% and was extended to on-market buying. The feed is more complete than it was. It still misses everything below 5%.

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1. The rule: 5%, five business days, 1%

Who files. Any holder whose shareholding ratio in a company listed on a Japanese exchange exceeds 5%. “Holder” is drawn widely: whoever owns the shares in its own or another’s name, whoever has a right to demand delivery (a buyer awaiting settlement, a margin buyer), and whoever has the power to invest under a discretionary mandate. [D — FSA FAQ; MMN law firm note]

What counts. The ratio is computed on share numbers, not voting rights. The numerator is the holder’s shares plus its “potential shares” (share options, convertible bonds, warrants); the denominator is the issuer’s shares in issue plus the holder’s own potential shares. [D — MMN; Daiwa Institute of Research]

Joint holders. The holdings of joint holders are added to the holder’s own. There are two kinds: anyone who has agreed with the holder to acquire or dispose of shares together, or to exercise voting and other shareholder rights together; and “deemed” joint holders by relationship, such as parent and subsidiary companies with a more-than-50% capital tie. [D — FSA FAQ; MMN; FSA Q&A, p.12]

Deadline. Within five business days from the day after the obligation arises. Business days exclude weekends and Japanese public holidays, which matters in practice: the filing in section 4 was triggered on Friday 24 April 2026 and lawfully filed on Thursday 7 May — 13 calendar days later, but exactly five business days once the 29 April and 4–6 May holidays are removed. [D — FSA FAQ; MMN; the filing itself]

Change report. After the first report, a change report is due, also within five business days, when the ratio rises or falls by 1 percentage point or more against the last filed figure; when the joint holders change; when the purpose of holding changes materially; or when a material contract on the shares — a pledge, a stock loan — is put on or taken off. [D — FSA FAQ; MMN; Daiwa Q12]

What the form contains. The issuer; the filer (name, address, business, a Japan contact); the purpose of holding; the material proposal acts the filer intends; the breakdown of holdings and the ratio; every acquisition or disposal in the last 60 days with date, quantity, on- or off-market, and price; important contracts on the shares (collateral, lending, joint-holding agreements); and the source of funds, including any borrowing and the lender’s name. [D — Daiwa Q17; MMN; Japan Law Guide]

Where it goes. Through EDINET to the Director-General of the Local Finance Bureau; non-resident filers report to the Kanto Local Finance Bureau. The filing is in Japanese. EDINET’s public site has a quick-search box with 大量保有報告書 as a document type and period filters from “today” to “all periods”; each document has an ID such as S100Y1ML and a PDF. Programmatic access needs a free API key. [D — MMN; EDINET site]

Penalties. Failing to file, or filing falsely, carries up to five years’ imprisonment or a ¥5 million fine, with a separate fine for the firm. There is also an administrative surcharge set at one hundred-thousandth of the issuer’s total market value. Only 13 surcharge orders have been issued since the surcharge was introduced in 2008, and an FSA working group proposed in December 2025 to recalibrate it. [D — MMN; Daiwa Q23]

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2. The special report: why a passive fund’s 5.2% is not news

The FIEA gives certain institutions a relaxed regime, the special report (特例報告, tokurei hōkoku). Eligible filers are securities firms, investment managers, banks, trust companies, insurers, and their foreign equivalents. [D — FSA FAQ; Daiwa Q18]

Under it, the filer does not report each trade. It checks its ratio only on two pre-registered basis dates a month — the second and fourth Mondays, or the 15th and the last day of the month — and files within five business days of a basis date if the ratio then exceeds 5% or has moved a point or more since the last filing. The form is also shorter: no 60-day trade list and no funding section. [D — FSA FAQ; FSA Q&A p.3; Daiwa Q17–Q19]

Three conditions attach, and they are what make the regime readable. The special report is not available if the ratio exceeds 10%, if the holder intends to acquire more than 10%, or if the purpose of holding is to make a material proposal. A holder who fails any of these drops into the ordinary five-business-day regime. [D — FSA Q&A p.3; Daiwa Q20]

So the filing regime itself is a label. A special-report filer at 5.2% is telling you it is a financial institution, under 10%, with no declared intent to press the company. Its intra-month moves are invisible by design: a position that goes from 4.9% to 5.4% and back between two basis dates never appears. [D — Daiwa Q18] That is why a custodian bank or an index manager crossing 5% is, for a reader of the feed, background.

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3. What changed on 1 May 2026

The Diet passed the amending Act on 15 May 2024, with enforcement to follow within two years by Cabinet Order. The FSA published draft Cabinet Orders on 14 March 2025 and the final ones in July 2025. The amended rules, the amended reporting form, and a new FSA Q&A apply from Friday 1 May 2026. [D — Nagashima Ohno & Tsunematsu; FSA; DLA Piper]

Joint holders, narrowed. Before, any agreement to vote together made the parties joint holders and forced them to aggregate. Now a collaborative engagement exemption applies if all three hold: the parties are institutional investors; the agreement’s purpose is not to make a material proposal together; and the agreement covers only an individual exercise of rights — made afresh for each shareholder meeting, on a resolution identified precisely, with both parties choosing for or against. A standing pact to vote against a named director for five years fails the first test. The FSA also confirmed that swapping views and finding you agree is not an “agreement”. [D — FSA Q&A pp.12–16; NO&T] Separately, the deemed-joint-holder list was revised: spouses were removed, and relationships through shared officers and funding were added. [D — note.com practitioner summary; M&A Capital Partners]

“Material proposal”, defined. An act is a material proposal only if it is a proposal to the issuer, on a matter in the Cabinet Order’s list, made with the intent to change the business materially. Asking management to explain its policy, or stating your own voting policy, is not a proposal. Big-impact matters — removing the representative director, nominating a named director, a merger, sale of the core business, a third-party takeover — count regardless of how they are raised. Smaller matters on the list, including dividend policy and capital policy, count only when made in a way that takes the decision out of management’s hands: a formal shareholder proposal, a public campaign, or a threat of either. [D — FSA Q&A pp.4–10] This is the line an activist’s “purpose” field now has to respect, and the FSA began reviewing every report filed after 1 May for whether holders were describing their intentions adequately. [D — Nikkei Asia, 4 July 2026]

Cash-settled derivatives, captured — conditionally. A holder of a long cash-settled equity derivative (a total return swap, for example) is now treated as a holder of the underlying shares if it has any of three purposes: to acquire the shares from the counterparty, to make a material proposal while showing the position, or to influence how the counterparty votes. The Cabinet Order sets a formula to convert the swap into a share-equivalent. A swap held purely for economic exposure is still outside the rule. [D — Daiwa; DLA Piper; Funds-Axis]

Tender offers. On the same day the mandatory tender-offer threshold fell from more than one-third to more than 30% of voting rights, chosen because 30% is generally enough to block a special resolution in a Japanese company, and the rule was extended to on-market purchases, which had been exempt. [D — NO&T Dec 2024; DLA Piper; Baker McKenzie] For the feed, this means 30% is now the ceiling a change-report sequence can approach without a tender offer.

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4. Reading the feed: one filing sequence

The example is Oasis Management’s 2026 position in Internet Initiative Japan (IIJ, 3774). It is used because both the filing and Tier-1 coverage were retrievable; nothing here is a view on either company.

The initial report (EDINET S100Y1ML). Obligation date 24 April 2026; filed 7 May 2026. Holding 13,723,994 shares, 7.48% of 183,448,852 shares in issue. Purpose of holding: “portfolio investment and material proposal acts”; material proposal field: “may make material proposals to protect shareholder value”. Funds: ¥36,441 million, all fund assets, no borrowing. Important contracts: none. The 60-day trade list shows 100 shares on 13 March, 6,800 on-market on 23 April, 300,000 off-market at ¥2,817 on 23 April, and 4,880,209 shares (2.66%) off-market at ¥2,761 on 24 April. [D — the filing] Reuters reported the 7.48% stake on 7 May. [D]

What each line tells you. The purpose line rules out the special report, so from here every one-point move is public within five business days. The trade list says the position was built in a block: 2.66% in one off-market print, on top of a stake already near 5%, not a drip through the market. The funds line says no leverage. The contracts line says no lending or hedging arrangement — which, since 1 May, would have had to be listed.

The sequence. On 13 May Reuters reported a further filing stating that Oasis would make a shareholder proposal. [D] On 1 July Reuters reported a change report taking the ratio to 9.07% from 8.04%. [D] The 8.04% filing itself was not retrieved; its date is unknown. Two readings follow. First, the 7.48%→8.04% step is under one point, so that report was triggered by something other than the ratio — most likely the change in stated intent — and it re-anchored the ratio, so the next mandatory report came at 9.07%. [S] Second, the pace: about 1.6 points in roughly nine weeks after a block-built entry, heading towards the 10% mark that shuts the special report for everyone and towards the 30% tender-offer line far above. The same week in May, Oasis crossed 5% in four other companies, one of which Nikkei Asia covered the day after filing. [D — Nikkei Asia, 13 May; Quorum]

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5. What the feed misses

• Everything below 5%. A 4.9% position never appears. A holder that sells from 6% to 4.5% files one last change report (the move is over a point) and then goes dark; one that drifts from 5.5% to 4.7% need not file until the cumulative move reaches a point. [D — Daiwa Q14] After that final report there is no exit filing; the reader simply stops seeing the name. [I]
• Special-report filers’ moves between basis dates, as in section 2.
• Cash-settled exposure without the stated intent. A swap held for economic exposure only is outside the rule even after May 2026. [D — Daiwa; DLA Piper] Whether a fund “has the purpose” to acquire is a fact about its intentions, so the line is enforced after the event, not observed in the feed. [I]
• The lag. Up to five business days from the trigger, and the trigger for a change report is the last filed ratio, not the last trade. In Golden Week or at year-end, five business days can be a fortnight.
• Lending double-counts; margin inventory does not count. Shares out on loan count for both lender and borrower, so the sum of filed ratios can exceed the true float held. A broker’s shares held against customers’ margin purchases are excluded from the broker’s ratio and counted by the customer. [D — Daiwa Q10, Q12] The practice of parking a position with a broker or in a swap to stay under 5% until ready is a widely understood tactic and one reason the derivative provision was written. [I]

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6. Japan against the US and the UK

[D — FSA; SEC press release 2023-219; Proskauer; FCA Handbook DTR 5.1.2R and 5.8.3R]

For an American reader, Japan is roughly 13D speed with no 13G-style quarterly regime for active holders; the special report is closer to 13G but with a hard 10% cap. For a British reader, Japan starts later (5%, not 3%) and reports slower (five business days, not two), but discloses more — the 60-day trade list and the funding source have no DTR 5 equivalent. [S]

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Caveats

• The statute text on the Japanese Law Translation database returned HTTP 403 throughout this session, so article references (27-23, 27-25, 27-26) are taken from the FSA’s own FAQ and Q&A document and from law-firm summaries, not from the translated Act.
• The 2024 Act’s enactment date: NO&T and the FSA describe the Diet passing the bill on 15 May 2024; Baker McKenzie describes 15 May as the date it was “enacted and promulgated”. The promulgation date was not independently confirmed.
• The final Cabinet Orders: DLA Piper dates them 4 July 2025; Funds-Axis says promulgated 1 July 2025 with consultation results on 4 July. The disagreement is recorded, not resolved.
• The tender-offer de minimis exemption is described as “less than 0.5% with no acquisitions in the previous six months” by Funds-Axis and as “less than 1% over a one-year period” in the March 2025 draft summary. The final figure was not retrieved and is omitted from the text.
• The Oasis/IIJ 8.04% change report was not retrieved; the ratio and the 1 July date come from Reuters headlines carried by third-party sites. The reading that the 8.04% filing was triggered by the change in stated intent is inference [S].
• The “>10,000 filings per year” figure is Daiwa Institute of Research’s statement, not an FSA count retrieved this session.
• Practices marked [I] — parking positions with brokers or in swaps, and enforcement of the derivative “purpose” test after the event — are industry-understood, with no single disclosing party.
• All rule descriptions are as retrieved on 3 September 2026. The FSA’s December 2025 working-group proposals on the surcharge had not been enacted at that date.

Sources [D]

All retrieved and confirmed to load on 3 September 2026.

Regulator — Japan

• FAQ on the Financial Instruments and Exchange Act, Section 5: Large shareholding reporting system — FSA — the 5% threshold, five business days, 1% change trigger, joint-holder definition, special-report basis dates, the 10% cut-off, EDINET as the filing route.
• Laws, regulations and Q&As on the “act of material proposal” and “joint holders” — FSA, 17 Sept 2025 and the document itself (PDF, dated 26 Aug 2025) — application from 1 May 2026; the three-part material-proposal test and the big-impact list; the special-report conditions; the collaborative engagement exemption and its three conditions; the overview on p.17.
• EDINET public site — FSA — the quick-search with 大量保有報告書 as a document type, the period filters, the API registration, and the FSA’s 28 April 2026 notice of its 2026 review of large shareholding reports.
• Oasis Management Company Ltd — Large Shareholding Report on Internet Initiative Japan, EDINET S100Y1ML (PDF) — every figure in section 4’s first two paragraphs.

Regulators — US and UK

• SEC adopts amendments to rules governing beneficial ownership reporting — SEC, 10 Oct 2023 — 13D initial deadline cut to five business days, amendments to two business days, 13G compliance by 30 Sept 2024, XML by 18 Dec 2024, cash-settled derivative guidance.
• New filing deadlines for Schedule 13G effective September 30 — Proskauer — the 13G deadlines by filer type and the 1% materiality reference for 13D.
• FCA Handbook DTR 5.1 — Notification of the acquisition or disposal of major shareholdings — 3% and each 1% thereafter for UK issuers; 5/10/15/20/25/30/50/75% for non-UK issuers.
• FCA Handbook DTR 5.8 — Procedures for notification — two trading days (four for non-UK issuers); issuer publication by end of the next trading day.

Law firms and practitioners — Japan

• Submission of a Large Shareholding Report — MMN law office, Dec 2025 (PDF) — the holder definition, the ratio formula, the form’s contents, Kanto Local Finance Bureau for non-residents, “five business days from the day following”, penalties and the 1/100,000 surcharge, change-report triggers.
• Large shareholding reporting (5% rule) Q&A, revised for the 1 May 2026 amendments — Daiwa Institute of Research, 3 April 2026 (PDF, Japanese) — the special-report eligibility list and basis dates (Q18–Q20), the form contents (Q17), lending and margin treatment (Q10, Q12), below-5% cases (Q14), the derivative purposes and conversion formulae, penalties and the 13 surcharge orders and >10,000 filings a year (Q23).
• Amendments to the Large Shareholding Reporting System — Nagashima Ohno & Tsunematsu, Sept 2024 and the same in Legal 500 — Diet passage 15 May 2024, effect within two years, the joint-holder exemption conditions, the material-proposal clarification.
• Amendments to the Tender Offer Regulations — Nagashima Ohno & Tsunematsu, Dec 2024 — one-third to 30%, the special-resolution rationale, on-market purchases brought in, the rapid-acquisition rule removed.
• Recent developments on TOB rules and shareholding transparency in Japan — DLA Piper, Jan 2026 — enforcement of the legislative amendment on 1 May 2026, final Cabinet Orders 4 July 2025, cash-settled derivatives, the FSA working-group report of 25 Dec 2023.
• Japan — General legal framework, Global Public M&A Guide — Baker McKenzie — 30% rule and on-market application from the effective date; enforcement within two years of 15 May 2024.
• Japan’s 2024 FIEA amendments: key shareholder disclosure reforms coming in 2026 — Funds-Axis — 1 May 2026; cash-settled derivatives and the conversion method; Cabinet Order dates as it states them.
• Japan — FSA publication of draft Cabinet Orders (2024 FIEA amendments) — Global Disclosures — drafts published 14 March 2025.
• Japan new 5% rule reforms in 2026 — KizunaX — corroboration that the derivative inclusion is intention-dependent.
• Large Shareholding Reports (the 5% Rule) — Japan Law Guide — form contents including the 60-day trade list; filings in Japanese via EDINET.
• How to navigate the Japanese shareholding regime — FundApps — the 5–10% special-report window and the re-anchoring of the 1% trigger at each filing.
• 大量保有報告とは — M&A Capital Partners (Japanese) — the form’s contents, penalties, and the five points of the May 2026 amendment including the removal of spouses from deemed joint holders.
• 2026年5月施行 大量保有報告制度改正の概要 — practitioner note on note.com (Japanese) — 1 May 2026 for both the reporting and TOB changes; the deemed-joint-holder revisions; the three derivative purposes.
• 【2026年5月施行】大量保有報告 改正5つのポイント — 企業法務弁護士ナビ (Japanese) — corroboration of the 1 May 2026 date and the amendment’s five points.
• Data sources — Japan Finsight — EDINET document type 350 for large shareholding reports; filings are in Japanese.

Press — the worked example and the FSA review

• Oasis Management holds 7.48% stake in Internet Initiative Japan, filing shows — Reuters via MarketScreener, 7 May 2026 and IIJ news list — MarketScreener — the 7 May and 13 May Reuters headlines.
• Oasis raises stake in Internet Initiative Japan to 9.07% from 8.04%, filing shows — Reuters via Stockopedia, 1 July 2026 — the 9.07%/8.04% step and its date.
• Hong Kong activist investor Oasis reports 5.4% stake in Japan’s Kanadevia — Nikkei Asia, 13 May 2026 — a same-week filing, reported the day after.
• Oasis Management’s 7.48% stake in IIJ — Quorum and Oasis Management’s Japan positions, 2026 — Quorum — the EDINET document IDs and the list of five May 2026 crossings (used only for the IDs and the count).
• Japan probes shareholding reports as activist proposals mount — Nikkei Asia, 4 July 2026 — the FSA reviewing all large shareholding reports filed after 1 May for adequacy of stated intentions (headline and standfirst only; body paywalled).
• アクティビスト、変更届け出 大量保有報告制度の改正で相次ぐ — Nikkei, 20 May 2026 (Japanese, paywalled) — activists filing change reports with fuller purpose descriptions after 1 May.