As of November 6, 2026, 5 holders' latest Schedule 13D or 13G filings report owning 5% or more of NetScout Systems Inc. The largest reported stake is BlackRock, Inc.'s, at 14.8%. 9 filings are on record since July 9, 2025 (Schedule 13G/A, October 17, 2025).
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Key facts
- · Reporting person: Vanguard Capital Management · Sole voting: 546,253 · Shared voting: 0 · Sole dispositive: 3,612,886 · Shared dispositive: 0 · SCHEDULE 13G/A, 2026-10-30
- · Reporting person: State Street Corporation · Sole voting: 0 · Shared voting: 3,343,057 · Sole dispositive: 0 · Shared dispositive: 3,579,289 · SCHEDULE 13G, 2026-08-07
- · Holder: Vanguard Capital Management · Percent: 5.01% · SCHEDULE 13G
- · Reporting person: Legal & General Group Plc · Sole voting: 0 · Shared voting: 3,635,111 · Sole dispositive: 0 · Shared dispositive: 3,635,111 · SCHEDULE 13G, 2026-05-08
- · Reporting person: Vanguard Portfolio Management · Sole voting: 83,617 · Shared voting: 0 · Sole dispositive: 5,612,461 · Shared dispositive: 0 · SCHEDULE 13G, 2026-04-29
NetScout Systems Inc has 9 Schedule 13D or 13G filings on record since 2025-07-09. 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. | 14.8% | 10,603,782 | SCHEDULE 13G/A, 2025-10-17 | 2025-09-30 |
| Vanguard Portfolio Management | 7.77% | 5,612,461 | SCHEDULE 13G, 2026-04-29 | 2026-03-31 |
| Legal & General Group Plc | 5.69% | 4,037,807 | SCHEDULE 13G/A, 2025-07-09 | 2023-12-31 |
| Legal & General Group Plc | 5% | 3,635,111 | SCHEDULE 13G, 2026-05-08 | 2026-03-31 |
| State Street Corporation | 5% | 3,579,289 | SCHEDULE 13G, 2026-08-07 | 2026-06-30 |
| Vanguard Capital Management | 4.96% | 3,612,886 | SCHEDULE 13G/A, 2026-10-30 | 2026-09-30 |
| The Vanguard Group | 0% | 0 | SCHEDULE 13G/A, 2026-03-27 | 2026-03-13 |
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More on NetScout Systems Inc and the records around it.
NetScout Systems Inc elsewhere on the record
Companies that share a holder
- Legal & General Group Plc also filed stake reports on 4 other companies: Fastly, Inc. (Aug 2026), FUELCELL ENERGY, INC. (Aug 2026), ZIFF DAVIS, INC. (Aug 2026)
- Legal & General Group Plc also filed stake reports on 7 other companies: A10 NETWORKS, INC. (Jul 2025), Fastly, Inc. (Jul 2025), Eos Energy Enterprises, Inc. (Jul 2025)
- STATE STREET CORPORATION also filed stake reports on 343 other companies: TRADE DESK INC/THE (Oct 2026), CENTRUS ENERGY CORP (Sep 2026), ACADIA PHARMACEUTICALS INC (Aug 2026)
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Voting and dispositive power, as filed
| Reporting person | Sole voting | Shared voting | Sole dispositive | Shared dispositive | Filing |
|---|---|---|---|---|---|
| Vanguard Portfolio Management | 83,617 | 0 | 5,612,461 | 0 | SCHEDULE 13G, 2026-04-29 |
| Legal & General Group Plc | 0 | 3,635,111 | 0 | 3,635,111 | SCHEDULE 13G, 2026-05-08 |
| Legal & General Investment Management Ltd | 0 | 3,529,368 | 0 | 3,529,368 | SCHEDULE 13G, 2026-05-08 |
| LGIM Managers (Europe) Limited | 0 | 3,487,773 | 0 | 3,487,773 | SCHEDULE 13G, 2026-05-08 |
| Legal & General UCITS ETF Plc | 0 | 3,472,994 | 0 | 3,472,994 | SCHEDULE 13G, 2026-05-08 |
| Legal & General Investment Management America Inc | 0 | 105,743 | 0 | 105,743 | SCHEDULE 13G, 2026-05-08 |
| LGIM Singapore PTE Ltd | 0 | 0 | 0 | 14,779 | SCHEDULE 13G, 2026-05-08 |
| State Street Corporation | 0 | 3,343,057 | 0 | 3,579,289 | SCHEDULE 13G, 2026-08-07 |
| Vanguard Capital Management | 546,253 | 0 | 3,612,886 | 0 | SCHEDULE 13G/A, 2026-10-30 |
The latest filing identifies NetScout Systems Inc by CUSIP 64115T104 and gives its principal executive office as 310 Littleton Road, Westford, MA 01886 (SCHEDULE 13G/A, 2026-10-30).
Timeline
| Filed | Holder | Percent | Filing |
|---|---|---|---|
| 2025-07-09 | Legal & General Group Plc | 5.69% | SCHEDULE 13G/A |
| 2025-08-11 | Legal & General Group Plc | 6.3% | SCHEDULE 13G |
| 2025-10-17 | BlackRock, Inc. | 14.8% | SCHEDULE 13G/A |
| 2026-03-27 | The Vanguard Group | 0% | SCHEDULE 13G/A |
| 2026-04-29 | Vanguard Portfolio Management | 7.77% | SCHEDULE 13G |
| 2026-05-08 | Legal & General Group Plc | 5% | SCHEDULE 13G |
| 2026-07-31 | Vanguard Capital Management | 5.01% | SCHEDULE 13G |
| 2026-08-07 | State Street Corporation | 5% | SCHEDULE 13G |
| 2026-10-30 | Vanguard Capital Management | 4.96% | SCHEDULE 13G/A |
Questions about who owns NetScout Systems Inc
Who owns NetScout Systems Inc?
On this page, 5 holders' latest ownership filings report 5% or more of NetScout Systems Inc: BlackRock, Inc. (14.8%, Schedule 13G/A, filed 2025-10-17), Vanguard Portfolio Management (7.77%, Schedule 13G, filed 2026-04-29), Legal & General Group Plc (5.69%, Schedule 13G/A, filed 2025-07-09), Legal & General Group Plc (5%, Schedule 13G, filed 2026-05-08) and State Street Corporation (5%, Schedule 13G, filed 2026-08-07).
Who are the largest shareholders of NetScout Systems Inc?
By the share each holder's latest filing reports, the largest holders of NetScout Systems Inc on this page are BlackRock, Inc. (14.8%), Vanguard Portfolio Management (7.77%) and Legal & General Group Plc (5.69%).
When did BlackRock, Inc. buy into NetScout 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 2025-10-17, reporting 14.8%. 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%); 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 NetScout Systems Inc
| Date | Record | Figure | Our page | Source |
|---|---|---|---|---|
| October 26, 2026 | Leadership change filing (Form 8-K, Item 5.02) | — | 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.