As of November 6, 2026, 5 holders' latest Schedule 13D or 13G filings report owning 5% or more of Osi Systems Inc. The largest reported stake is BlackRock, Inc.'s, at 15.2%. 15 filings are on record since July 18, 2025 (Schedule 13G/A, October 27, 2026).
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Key facts
- · Reporting person: Fmr LLC · Sole voting: 1,069,435 · Shared voting: 0 · Sole dispositive: 1,070,738 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-11-05
- · Reporting person: BlackRock, Inc. · Sole voting: 2,397,084 · Shared voting: 0 · Sole dispositive: 2,429,562 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-10-27
- · Reporting person: JANUS HENDERSON GROUP Ltd. · Sole voting: 0 · Shared voting: 905,925 · Sole dispositive: 0 · Shared dispositive: 905,925 · SCHEDULE 13G, 2026-08-13
- · Holder: Fmr LLC · Percent: 10.8% · SCHEDULE 13G/A
- · Reporting person: Vanguard Capital Management · Sole voting: 121,440 · Shared voting: 0 · Sole dispositive: 824,510 · Shared dispositive: 0 · SCHEDULE 13G, 2026-07-31
Osi Systems Inc has 15 Schedule 13D or 13G filings on record since 2025-07-18. 5 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 |
|---|---|---|---|---|
| BlackRock, Inc. | 15.2% | 2,429,562 | SCHEDULE 13G/A, 2026-10-27 | 2026-09-30 |
| Vanguard Portfolio Management | 7.66% | 1,263,421 | SCHEDULE 13G, 2026-04-29 | 2026-03-31 |
| Fmr LLC | 6.7% | 1,070,738 | SCHEDULE 13G/A, 2026-11-05 | 2026-09-30 |
| JANUS HENDERSON GROUP Ltd. | 5.5% | 905,925 | SCHEDULE 13G, 2026-08-13 | 2026-06-30 |
| Vanguard Capital Management | 5% | 824,510 | SCHEDULE 13G, 2026-07-31 | 2026-06-30 |
| Mawer Investment Management Ltd. | 4.73% | 803,602 | SCHEDULE 13G/A, 2026-02-11 | 2025-12-31 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-27 | 2026-03-13 |
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More on Osi Systems Inc and the records around it.
Osi Systems Inc elsewhere on the record
Companies that share a holder
- Mawer Investment Management Ltd. also filed stake reports on 10 other companies: Barrett Business Services Inc (Aug 2026), North American Construction Group Ltd. (May 2026), Warner Music Group Corp. (Nov 2025)
- JANUS HENDERSON GROUP PLC also filed stake reports on 104 other companies: SURGERY PARTNERS, INC. (Nov 2026), EYEPOINT, INC. (Sep 2026), TELEFLEX INCORPORATED (Sep 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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What the Full Report on Osi Systems Inc covers
The Short Answer
Which Company This Is
What They Do, And How The Money Works
Who Runs It, And How To Reach Them
The Money: Funding, Valuation, Runway
Who Pays Them, And Who They Are Up Against
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| BlackRock, Inc. | 2,397,084 | 0 | 2,429,562 | 0 | SCHEDULE 13G/A, 2026-10-27 |
| Fmr LLC | 1,069,435 | 0 | 1,070,738 | 0 | SCHEDULE 13G/A, 2026-11-05 |
| Abigail P. Johnson | 0 | 0 | 1,070,738 | 0 | SCHEDULE 13G/A, 2026-11-05 |
| JANUS HENDERSON GROUP Ltd. | 0 | 905,925 | 0 | 905,925 | SCHEDULE 13G, 2026-08-13 |
| Vanguard Capital Management | 121,440 | 0 | 824,510 | 0 | SCHEDULE 13G, 2026-07-31 |
The latest filing identifies Osi Systems Inc by CUSIP 671044105 and gives its principal executive office as 12525 CHADRON AVE, HAWTHORNE, CA 90250 (SCHEDULE 13G/A, 2026-11-05).
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-07-18 | BlackRock, Inc. | 14.2% | SCHEDULE 13G/A |
| 2025-08-14 | Janus Henderson Group Plc | 6.3% | SCHEDULE 13G/A |
| 2025-11-12 | Mawer Investment Management Ltd. | 5.09% | SCHEDULE 13G |
| 2025-11-14 | Janus Henderson Group Plc | 5.9% | SCHEDULE 13G/A |
| 2026-01-08 | Fmr LLC | 10% | SCHEDULE 13G/A |
| 2026-02-11 | Mawer Investment Management Ltd. | 4.73% | SCHEDULE 13G/A |
| 2026-03-27 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-04-29 | Vanguard Portfolio Management | 7.66% | SCHEDULE 13G |
| 2026-05-06 | Fmr LLC | 12.6% | SCHEDULE 13G/A |
| 2026-05-15 | Janus Henderson Group Plc | 4.7% | SCHEDULE 13G/A |
| 2026-07-31 | Vanguard Capital Management | 5% | SCHEDULE 13G |
| 2026-08-06 | Fmr LLC | 10.8% | SCHEDULE 13G/A |
| 2026-08-13 | JANUS HENDERSON GROUP Ltd. | 5.5% | SCHEDULE 13G |
| 2026-10-27 | BlackRock, Inc. | 15.2% | SCHEDULE 13G/A |
| 2026-11-05 | Fmr LLC | 6.7% | SCHEDULE 13G/A |
Questions about who owns Osi Systems Inc
Who owns Osi Systems Inc?
On this page, 5 holders' latest ownership filings report 5% or more of Osi Systems Inc: BlackRock, Inc. (15.2%, Schedule 13G/A, filed 2026-10-27), Vanguard Portfolio Management (7.66%, Schedule 13G, filed 2026-04-29), Fmr LLC (6.7%, Schedule 13G/A, filed 2026-11-05), JANUS HENDERSON GROUP Ltd. (5.5%, Schedule 13G, filed 2026-08-13) and Vanguard Capital Management (5%, Schedule 13G, filed 2026-07-31).
Who are the largest shareholders of Osi Systems Inc?
By the share each holder's latest filing reports, the largest holders of Osi Systems Inc on this page are BlackRock, Inc. (15.2%), Vanguard Portfolio Management (7.66%) and Fmr LLC (6.7%).
When did BlackRock, Inc. buy into Osi Systems Inc?
The filings give report dates, not purchase dates. The earliest filing from BlackRock, Inc. on this page is the Schedule 13G/A, filed 2025-07-18, reporting 14.2%; its latest, Schedule 13G/A filed 2026-10-27, reports 15.2%. That earliest filing is itself an amendment, which updates an earlier report.
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%); 15 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.
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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.