As of November 7, 2026, 4 holders' latest Schedule 13D or 13G filings report owning 5% or more of Kiniksa Pharmaceuticals International, plc. The largest reported stake is Fmr LLC's, at 14.8%. 9 filings are on record since July 9, 2025 (Schedule 13G/A, May 6, 2026).
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Key facts
- · Reporting person: BlackRock, Inc. · Sole voting: 2,470,912 · Shared voting: 0 · Sole dispositive: 2,534,789 · Shared dispositive: 0 · SCHEDULE 13G, 2026-07-29
- · Holder: Baker Bros. Advisors LP · Percent: 7% · SCHEDULE 13D/A
- · Holder: Fmr LLC · Percent: 14.8% · SCHEDULE 13G/A
- · Holder: The Vanguard Group · Percent: 0% · SCHEDULE 13G/A
- · Holder: Fmr LLC · Percent: 10.6% · SCHEDULE 13G
Kiniksa Pharmaceuticals International, plc has 9 Schedule 13D or 13G filings on record since 2025-07-09. 4 holders' latest filing reports 5% or more of common stock. Each figure below is the holder's own, as filed, with the filing linked.
Holders
| Holder | Percent | Shares | Latest | Event date |
|---|---|---|---|---|
| Fmr LLC | 14.8% | 6,787,700 | SCHEDULE 13G/A, 2026-05-06 | 2026-03-31 |
| Rubric Capital Management LP | 7.37% | 3,328,653 | SCHEDULE 13G/A, 2026-02-13 | 2025-12-31 |
| Baker Bros. Advisors LP | 7% | 3,231,181 | SCHEDULE 13D/A, 2026-05-26 | 2026-05-21 |
| BlackRock, Inc. | 5.5% | 2,534,789 | SCHEDULE 13G, 2026-07-29 | 2026-06-30 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-27 | 2026-03-13 |
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More on Kiniksa Pharmaceuticals International, plc and the records around it.
Kiniksa Pharmaceuticals International, plc elsewhere on the record
- Leadership changes May 2026
- Who owns it
Companies that share a holder
- Baker Bros. Advisors LP also filed stake reports on 25 other companies: Madrigal Pharmaceuticals, Inc. (Nov 2026), Kodiak Sciences Inc. (Sep 2026), BeOne Medicines Ltd. (Sep 2026)
- Rubric Capital Management LP also filed stake reports on 32 other companies: ARDELYX, INC. (Aug 2026), Enovis Corporation (Aug 2026), MeiraGTx Holdings plc (Aug 2026)
- FMR LLC also filed stake reports on 761 other companies: ASPEN NEUROSCIENCE INC (Nov 2026), AVALO THERAPEUTICS INC (Nov 2026), BRAZE INC (Nov 2026)
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| BlackRock, Inc. | 2,470,912 | 0 | 2,534,789 | 0 | SCHEDULE 13G, 2026-07-29 |
The latest filing identifies Kiniksa Pharmaceuticals International, plc by CUSIP G52694109 and gives its principal executive office as 105 Piccadilly, Second Floor, LONDON (SCHEDULE 13G, 2026-07-29).
Purpose of Transaction (Item 4)
Baker Bros. Advisors LP
Item 4 of Schedule 13D is supplemented and amended, as the case may be, as follows: On May 21, 2026, Kiniksa Pharmaceuticals International, plc (the "Issuer") and the Adviser on behalf of the Funds entered into a Deed of Waiver (the "Deed") according to which the Adviser on behalf of the Funds irrevocably and unconditionally waived the Funds' right to convert the Class A1 ordinary shares of the Issuer ("Class A1 ordinary shares") and Class B1 ordinary shares of the Issuer ("Class B1 ordinary shares") held by the Funds into Class A ordinary shares of the Issuer ("Class A ordinary shares") or Class B ordinary shares of the Issuer ("Class B ordinary shares") to the extent that, immediately prior to or following the exercise of such conversion, the Funds (together with their direct or indirect affiliates, any person or entity who could be deemed to be acting as a "group" pursuant to Section 13(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act") together with the Funds or any of their affiliates, and any other persons or entities whose beneficial ownership of the Issuer's ordinary shares would or could be aggregated with the Funds' and/or any of their affiliates' for purposes of Section 13(d) or Section 16 of the Exchange Act) would beneficially own more than 49.9% of the outstanding voting rights in the Issuer. The Issuer agreed pursuant to the Deed not to effect the putative exercise of any conversion rights of the Funds' Class A1 ordinary shares or …The first part of Item 4 of the SCHEDULE 13D/A filed 2026-05-26; the filing has the rest
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-07-09 | Rubric Capital Management LP | 9.24% | SCHEDULE 13G/A |
| 2025-07-17 | BlackRock, Inc. | 1% | SCHEDULE 13G/A |
| 2025-10-31 | The Vanguard Group | 7.04% | SCHEDULE 13G/A |
| 2026-02-13 | Rubric Capital Management LP | 7.37% | SCHEDULE 13G/A |
| 2026-03-06 | Fmr LLC | 10.6% | SCHEDULE 13G |
| 2026-03-27 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-05-06 | Fmr LLC | 14.8% | SCHEDULE 13G/A |
| 2026-05-26 | Baker Bros. Advisors LP | 7% | SCHEDULE 13D/A |
| 2026-07-29 | BlackRock, Inc. | 5.5% | SCHEDULE 13G |
Questions about who owns Kiniksa Pharmaceuticals International, plc
Who owns Kiniksa Pharmaceuticals International, plc?
On this page, 4 holders' latest ownership filings report 5% or more of Kiniksa Pharmaceuticals International, plc: Fmr LLC (14.8%, Schedule 13G/A, filed 2026-05-06), Rubric Capital Management LP (7.37%, Schedule 13G/A, filed 2026-02-13), Baker Bros. Advisors LP (7%, Schedule 13D/A, filed 2026-05-26) and BlackRock, Inc. (5.5%, Schedule 13G, filed 2026-07-29).
Who are the largest shareholders of Kiniksa Pharmaceuticals International, plc?
By the share each holder's latest filing reports, the largest holders of Kiniksa Pharmaceuticals International, plc on this page are Fmr LLC (14.8%), Rubric Capital Management LP (7.37%) and Baker Bros. Advisors LP (7%).
When did Fmr LLC buy into Kiniksa Pharmaceuticals International, plc?
The filings give report dates, not purchase dates. The earliest filing from Fmr LLC on this page is the Schedule 13G, filed 2026-03-06, reporting 10.6%; its latest, Schedule 13G/A filed 2026-05-06, reports 14.8%.
Is this an audit or a full list?
Neither. The ownership list on this page covers only Schedule 13D and 13G filings, which holders make once they own 5% or more of a class of shares (an amendment can report a stake that has since fallen below 5%); 9 such filings are shown here. It is not an audit and not a full cap table: holders who never reached 5% are not listed, and a stake can change after its latest filing.
Also on the record for Kiniksa Pharmaceuticals International, plc
| Date | Record | Figure | Our page | Source |
|---|---|---|---|---|
| October 22, 2026 | Leadership change: Ross Moat appointed, Chief Operating Officer | — | Leadership changes | Source |
| May 1, 2026 | Leadership change: Eben Tessari departs, Chief Strategy Officer, and 1 more | — | Leadership changes | Source |
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Where this comes from
Anyone who comes to own more than 5% of a class of a listed company's voting shares has to tell the SEC. A holder who may seek to change or influence the company files Schedule 13D, and has to say in Item 4, "Purpose of Transaction", what it intends to do. A holder with no such intent, such as many index and passive funds, may file the shorter Schedule 13G. Both are amended when the stake changes, including when it falls below 5%.
Every row here is one of those filings, linked to the filing itself. Percentages and share counts are exactly as the holder filed them, for the holder the filing names; an amendment showing a lower figure is shown as filed. Item 4 text is quoted word for word. Where a 13D's Item 4 contains a sentence stating a definite intent to influence the company, that sentence is marked and quoted; the page does not describe the holder or its motives beyond the words it filed. Nothing here is investment advice.