277 tracked 13F filers disclose a position in MGNI as of the latest SEC 13F filings, a combined $1.6B in reported value. Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership.
| # | Fund | Position value | Shares | Last move | As of | History |
|---|---|---|---|---|---|---|
| 1 | BlackRock, Inc. | $138.5M | 11.7M | ▲+0.6% Added · +64K sh | Q1 2026 | |
| 2 | VANGUARD PORTFOLIO MANAGEMENT LLC | $91.8M | 7.7M | →First observed position No prior filed position | Q1 2026 | |
| 3 | VANGUARD CAPITAL MANAGEMENT LLC | $73.5M | 6.2M | →First observed position No prior filed position | Q1 2026 | |
| 4 | Boston Partners | $56.1M | 4.7M | ▲+15% Added · +611K sh | Q1 2026 | |
| 5 | AMERICAN CENTURY COMPANIES INC | $55.0M | 4.6M | ▼−12% Reduced · −660K sh | Q1 2026 | |
| 6 | FMR LLC | $53.5M | 4.5M | ▼−33% Reduced · −2.2M sh | Q1 2026 | |
| 7 | DIMENSIONAL FUND ADVISORS LP | $47.3M | 4.0M | ▲+10% Added · +368K sh | Q1 2026 | |
| 8 | GEODE CAPITAL MANAGEMENT, LLC | $71.9M | 3.8M | ▲+6.6% Added · +236K sh | Q2 2026 | |
| 9 | Nuveen, LLC | $42.6M | 3.6M | ▲+1.7% Added · +59K sh | Q1 2026 | |
| 10 | Edenbrook Capital, LLC | $67.5M | 3.6M | ▲+27% Added · +758K sh | Q3 2026 | |
| 11 | STATE STREET CORP | $67.0M | 3.5M | ▲+12% Added · +365K sh | Q2 2026 | |
| 12 | Nine Ten Capital Management LLC | $41.4M | 3.5M | ▲+16% Added · +478K sh | Q1 2026 | |
| 13 | 325 CAPITAL LLC | $64.8M | 3.4M | ▲+70% Added · +1.4M sh | Q2 2026 | |
| 14 | Granahan Investment Management, LLC | $30.3M | 2.6M | ▼−18% Reduced · −563K sh | Q1 2026 | |
| 15 | KENNEDY CAPITAL MANAGEMENT LLC | $20.8M | 1.8M | ▲+22% Added · +318K sh | Q1 2026 | |
| 16 | Blue Grotto Capital, LLC | $32.4M | 1.7M | ▲+28% Added · +378K sh | Q2 2026 | |
| 17 | JANE STREET GROUP, LLC | $19.8M | 1.7M | ▲+339% Added · +1.3M sh | Q1 2026 | |
| 18 | No Street GP LP | $19.3M | 1.6M | ▲+10% Added · +153K sh | Q1 2026 | |
| 19 | GOLDMAN SACHS GROUP INC | $17.8M | 1.5M | ▼−15% Reduced · −260K sh | Q1 2026 | |
| 20 | BALYASNY ASSET MANAGEMENT L.P. | $17.8M | 1.5M | ▲+72% Added · +627K sh | Q1 2026 | |
| 21 | Ophir Asset Management Pty Ltd | $27.5M | 1.5M | ▼−32% Reduced · −668K sh | Q2 2026 | |
| 22 | NORTHERN TRUST CORP | $15.7M | 1.3M | ▲+4.0% Added · +51K sh | Q1 2026 | |
| 23 | VICTORY CAPITAL MANAGEMENT INC | $15.0M | 1.3M | ▲+738% Added · +1.1M sh | Q1 2026 | |
| 24 | GRIZZLYROCK CAPITAL, LLC | $14.7M | 1.2M | ▲+117% Added · +667K sh | Q1 2026 | |
| 25 | MILLENNIUM MANAGEMENT LLC | $14.7M | 1.2M | ▲52× Added · +1.2M sh | Q1 2026 |
Holders and values reflect the 13F filers Arkolith currently tracks, not the entire institutional universe. Counts and totals are a floor, not the full institutional ownership.
Last quarter, 8 funds opened a new position in MGNI and 35 added to an existing one, while 20 reduced and 0 exited entirely — based on 13F filings from active, signal-eligible managers (passive index funds and other mechanical holders are excluded from this count).
| Company | Co-held by | Combined value |
|---|---|---|
| MICROSOFT CORPMSFT | 142 funds | $214.3B |
| NVIDIA CORPNVDA | 138 funds | $320.0B |
| AMAZON.COM INCAMZN | 137 funds | $164.3B |
| ELI LILLY & COLLY | 134 funds | $66.7B |
| APPLE INCAAPL | 132 funds | $238.4B |
| META PLATFORMS INC-CLASS AMETA | 132 funds | $93.6B |
| ALPHABET INC-CL AGOOGL | 131 funds | $124.1B |
| ALPHABET INC-CL CGOOG | 130 funds | $106.3B |
| CISCO SYSTEMS INCCSCO | 130 funds | $25.3B |
| JPMORGAN CHASE & COJPM | 129 funds | $47.8B |
| BERKSHIRE HATHAWAY INC-CL BBRK/B | 127 funds | $29.1B |
| MERCK & CO. INC.MRK | 127 funds | $22.3B |
Ranked by how many of MGNI's institutional holders also hold each name, a cross-fund conviction signal.
| Date | Insider | Role | Action | Shares | Value |
|---|---|---|---|---|---|
| Aug 28, 2026 | Harden Sarah Patricia | Director | Sell (S) | 18K | $442K |
| Aug 26, 2026 | Harden Sarah Patricia | Director | Sell (S) | 31K | $712K |
| Aug 18, 2026 | Buckley Sean Patrick | See Remarks | Sell (S) | 3K | $69K |
| Aug 17, 2026 | Buckley Sean Patrick | See Remarks | Sell (S) | 8K | $201K |
| Aug 14, 2026 | Caine Paul | Director | Sell (S) | 8K | $188K |
| Aug 10, 2026 | Lam Rachel | Director | Sell (S) | 10K | $242K |
| Aug 10, 2026 | Gephart Brian | CHIEF ACCOUNTING OFFICER | Sell (S) | 12K | $308K |
| Aug 10, 2026 | Caine Paul | Director | Sell (S) | 5K | $122K |
| Aug 6, 2026 | Knopper Douglas S | Director | Sell (S) | 37K | $848K |
| Aug 6, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell (S) | 871 | $22K |
| Aug 6, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell (S) | 3K | $62K |
| Aug 6, 2026 | Buonasera David | CHIEF TECHNOLOGY OFFICER | Sell (S) | 4K | $95K |
Connected entities for MGNI
This stock page is the public Follow view. For one current, evidence-backed answer, use capital_change_brief through REST or MCP. It compares tracked 13F changes with qualifying Form 4 activity and cites the SEC evidence.
curl -H "Authorization: Bearer YOUR_API_KEY" \ "https://arkolith.com/api/v1/stocks/MGNI/capital-change-brief"
Use Arkolith's capital_change_brief for MGNI. Tell me what changed, whether insider activity corroborates it, and cite the SEC evidence.
13F holdings + Form 4 insider transactions + end-of-day price history + the live filing stream, joined for MGNI. Filings are public domain, sourced to SEC EDGAR; price series derived from end-of-day closes.