197 tracked 13F filers disclose a position in MASI as of the latest SEC 13F filings, a combined $8.0B 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. | $826.1M | 4.6M | ▼−48% Reduced · −4.2M sh | Q1 2026 | |
| 2 | Politan Capital Management LP | $816.4M | 4.6M | —Held | Q1 2026 | |
| 3 | Pentwater Capital Management LP | $564.9M | 3.2M | ▲New +3.2M sh | Q1 2026 | |
| 4 | BARCLAYS PLC | $488.1M | 2.7M | ▲47× Added · +2.7M sh | Q1 2026 | |
| 5 | HBK INVESTMENTS L P | $458.2M | 2.6M | ▲New +2.6M sh | Q1 2026 | |
| 6 | MASSACHUSETTS FINANCIAL SERVICES CO /MA/ | $416.7M | 2.3M | ▼−12% Reduced · −321K sh | Q1 2026 | |
| 7 | VANGUARD CAPITAL MANAGEMENT LLC | $364.6M | 2.1M | →First observed position No prior filed position | Q1 2026 | |
| 8 | VANGUARD PORTFOLIO MANAGEMENT LLC | $357.0M | 2.0M | →First observed position No prior filed position | Q1 2026 | |
| 9 | FMR LLC | $258.1M | 1.5M | ▼−82% Reduced · −6.4M sh | Q1 2026 | |
| 10 | MILLENNIUM MANAGEMENT LLC | $175.9M | 989K | ▲+426% Added · +801K sh | Q1 2026 | |
| 11 | GOLDMAN SACHS GROUP INC | $175.1M | 984K | ▲+55% Added · +347K sh | Q1 2026 | |
| 12 | AQR CAPITAL MANAGEMENT LLC | $147.4M | 832K | ▼−24% Reduced · −259K sh | Q1 2026 | |
| 13 | BALYASNY ASSET MANAGEMENT L.P. | $137.1M | 771K | ▲New +771K sh | Q1 2026 | |
| 14 | MORGAN STANLEY | $133.8M | 752K | ▼−18% Reduced · −168K sh | Q1 2026 | |
| 15 | DAVIDSON KEMPNER CAPITAL MANAGEMENT LP | $104.2M | 586K | ▲New +586K sh | Q1 2026 | |
| 16 | JPMORGAN CHASE & CO | $101.5M | 573K | ▲+386% Added · +455K sh | Q1 2026 | |
| 17 | CITIGROUP INC | $94.9M | 533K | ▲+340% Added · +412K sh | Q1 2026 | |
| 18 | FIL Ltd | $85.7M | 482K | ▲New +482K sh | Q1 2026 | |
| 19 | First Trust Capital Management L.P. | $85.3M | 479K | ▲New +479K sh | Q1 2026 | |
| 20 | HSBC HOLDINGS PLC | $84.3M | 473K | ▲New +473K sh | Q1 2026 | |
| 21 | UBS Group AG | $83.3M | 468K | ▼−22% Reduced · −131K sh | Q1 2026 | |
| 22 | ALLIANCEBERNSTEIN L.P. | $59.2M | 455K | ▲+740% Added · +401K sh | Q1 2026 | |
| 23 | AQR Arbitrage LLC | $73.9M | 417K | ▲New +417K sh | Q1 2026 | |
| 24 | Neuberger Berman Group LLC | $71.7M | 403K | ▲81× Added · +398K sh | Q1 2026 | |
| 25 | NORTHERN TRUST CORP | $69.4M | 390K | ▲+2.6% Added · +10K 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, 27 funds opened a new position in MASI and 13 added to an existing one, while 14 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 |
|---|---|---|
| ELECTRONIC ARTS INCEA | 94 funds | $10.1B |
| META PLATFORMS INC-CLASS AMETA | 93 funds | $94.1B |
| WARNER BROS DISCOVERY INCWBD | 93 funds | $9.9B |
| NVIDIA CORPNVDA | 92 funds | $326.9B |
| AMAZON.COM INCAMZN | 92 funds | $168.8B |
| MICROSOFT CORPMSFT | 91 funds | $236.7B |
| BROADCOM INCAVGO | 91 funds | $132.6B |
| MICRON TECHNOLOGY INCMU | 91 funds | $27.5B |
| ALPHABET INC-CL AGOOGL | 90 funds | $137.3B |
| BOSTON SCIENTIFIC CORPBSX | 90 funds | $13.3B |
| APPLE INCAAPL | 89 funds | $245.0B |
| NORFOLK SOUTHERN CORPNSC | 89 funds | $10.5B |
Ranked by how many of MASI's institutional holders also hold each name, a cross-fund conviction signal.
| Date | Insider | Role | Action | Shares | Value |
|---|---|---|---|---|---|
| Jan 28, 2026 | Sampath Anand | EVP, Ops & Clinical Research | Sell (S) | 196 | $27K |
| Jan 28, 2026 | Sampath Anand | EVP, Ops & Clinical Research | Sell (S) | 7K | $900K |
| Jan 28, 2026 | Sampath Anand | EVP, Ops & Clinical Research | Sell (S) | 12K | $1.6M |
| Aug 13, 2025 | Brennan Michelle | Director | Buy (P) | 100 | $16K |
| Aug 12, 2025 | Brennan Michelle | Director | Buy (P) | 100 | $15K |
| Aug 11, 2025 | Jellison William R | Director | Buy (P) | 3K | $438K |
| May 12, 2025 | Muhsin Bilal | Chief Operating Officer | Sell (S) | 525 | $87K |
| May 12, 2025 | Muhsin Bilal | Chief Operating Officer | Sell (S) | 6K | $915K |
| May 12, 2025 | Muhsin Bilal | Chief Operating Officer | Sell (S) | 4K | $632K |
| Mar 14, 2025 | REYNOLDS CRAIG B | Director | Sell (S) | 2K | $341K |
| Mar 10, 2025 | Muhsin Bilal | Chief Operating Officer | Sell (S) | 2K | $392K |
| Mar 10, 2025 | Muhsin Bilal | Chief Operating Officer | Sell (S) | 4K | $650K |
Connected entities for MASI
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/MASI/capital-change-brief"
Use Arkolith's capital_change_brief for MASI. 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 MASI. Filings are public domain, sourced to SEC EDGAR; price series derived from end-of-day closes.