20 tracked 13F filers disclose a position in XLO as of the latest SEC 13F filings, a combined $17.7M 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 | Bain Capital Life Sciences Investors, LLC | $6.4M | 664K | —Held | Q2 2026 | |
| 2 | Frazier Life Sciences Management, L.P. | $4.0M | 423K | —Held | Q2 2026 | |
| 3 | Stonepine Capital Management, LLC | $2.2M | 226K | ▲+252% Added · +162K sh | Q2 2026 | |
| 4 | VANGUARD CAPITAL MANAGEMENT LLC | $1.0M | 124K | →First observed position No prior filed position | Q1 2026 | |
| 5 | Caligan Partners LP | $943K | 112K | ▲New +112K sh | Q1 2026 | |
| 6 | Merck & Co., Inc. | $1.0M | 106K | —Held | Q2 2026 | |
| 7 | MORGAN STANLEY | $484K | 57K | ▼−93% Reduced · −782K sh | Q1 2026 | |
| 8 | RENAISSANCE TECHNOLOGIES LLC | $417K | 50K | ▼−86% Reduced · −295K sh | Q1 2026 | |
| 9 | GEODE CAPITAL MANAGEMENT, LLC | $374K | 39K | ▲+5.0% Added · +2K sh | Q2 2026 | |
| 10 | FMR LLC | $307K | 37K | ▼−93% Reduced · −475K sh | Q1 2026 | |
| 11 | VANGUARD FIDUCIARY TRUST CO | $239K | 28K | →First observed position No prior filed position | Q1 2026 | |
| 12 | Velan Capital Investment Management LP | $137K | 14K | —Held | Q2 2026 | |
| 13 | STATE STREET CORP | $128K | 13K | —Held | Q2 2026 | |
| 14 | CWM, LLC | $35K | 4K | ▲New +4K sh | Q1 2026 | |
| 15 | UBS Group AG | $34K | 4K | ▲20× Added · +4K sh | Q1 2026 | |
| 16 | Steward Partners Investment Advisory, LLC | $7K | 714 | ▲New +714 sh | Q2 2026 | |
| 17 | JPMORGAN CHASE & CO | $2K | 240 | ▲New +240 sh | Q1 2026 | |
| 18 | Vanguard Global Advisers, LLC | $2K | 210 | →First observed position No prior filed position | Q1 2026 | |
| 19 | ROYAL BANK OF CANADA | $1K | 91 | ▲New +91 sh | Q1 2026 | |
| 20 | Key FInancial Inc | $565 | 59 | —Held | Q2 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, 1 fund opened a new position in XLO and 1 added to an existing one, while 1 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 |
|---|---|---|
| ADMA BIOLOGICS INCADMA | 4 funds | $62.5M |
| AVALO THERAPEUTICS INCAVTX | 4 funds | $32.2M |
| EXELIXIS INCEXEL | 3 funds | $655.4M |
| ALKERMES PLCALKS | 3 funds | $356.1M |
| MODERNA INCMRNA | 3 funds | $206.4M |
| KRYSTAL BIOTECH INCKRYS | 3 funds | $181.4M |
| SAVARA INCSVRA | 3 funds | $171.9M |
| MAZE THERAPEUTICS INCMAZE | 3 funds | $169.0M |
| PHATHOM PHARMACEUTICALS INCPHAT | 3 funds | $139.6M |
| DISC MEDICINE INCIRON | 3 funds | $111.5M |
| MINERALYS THERAPEUTICS INCMLYS | 3 funds | $85.8M |
| VOR BIOPHARMA INCVOR | 3 funds | $83.5M |
Ranked by how many of XLO's institutional holders also hold each name, a cross-fund conviction signal.
| Date | Insider | Role | Action | Shares | Value |
|---|---|---|---|---|---|
| Mar 26, 2026 | Shannon James Samuel | Director | Buy (P) | 5K | $44K |
| Jan 2, 2026 | Frankenfield Christopher James | Chief Financial Officer | Sell (S) | 7K | $4K |
| Jan 2, 2026 | Brennan Kevin M. | SVP, FINANCE AND ACCOUNTING | Sell (S) | 2K | $1K |
| Jun 17, 2025 | Shannon James Samuel | Director | Buy (P) | 25K | $17K |
| Jun 16, 2025 | Russo Rene | PRESIDENT AND CEO, Director | Buy (P) | 36K | $25K |
| Jun 16, 2025 | Shannon James Samuel | Director | Buy (P) | 45K | $31K |
| Jan 2, 2025 | Brennan Kevin M. | SVP, FINANCE AND ACCOUNTING | Sell (S) | 2K | $2K |
| Jan 2, 2025 | Frankenfield Christopher James | Chief Financial Officer | Sell (S) | 7K | $7K |
| Dec 18, 2024 | GILEAD SCIENCES, INC. | 10% Owner | Buy (P) | 1.8M | $1.8M |
| Apr 2, 2024 | GILEAD SCIENCES, INC. | 10% Owner | Buy (P) | 485K | $369K |
| Feb 8, 2024 | Atlas Venture Fund XI, L.P. | 10% Owner | Sell (S) | 267 | $171 |
| Feb 8, 2024 | Atlas Venture Fund XI, L.P. | 10% Owner | Sell (S) | 733 | $469 |
| Class | 13F holders | Value held |
|---|---|---|
| XLOthis pageCOMMON | 20 funds | $17.7M |
| 98422T100COM | 2 funds | $5.5M |
Same issuer, multiple share classes. The consensus leaderboards count this company once across all classes; this is the per-class detail.
Connected entities for XLO
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/XLO/capital-change-brief"
Use Arkolith's capital_change_brief for XLO. 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 XLO. Filings are public domain, sourced to SEC EDGAR; price series derived from end-of-day closes.