Who owns XLO (XLO)
Which tracked institutional funds hold XLO, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See XLO company fundamentals →
Ownership as of the 2026-Q1 13F filings. 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
4 tracked funds added or opened XLO while 6 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
XLO’s largest tracked holder by dollar value, Bain Capital Life Sciences Investors, LLC, sizes it at 0.5% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.5pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in XLO divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 24 tracked filers holding XLO, 8 increased or opened the position and 36 reduced or closed it; over the same quarter, open-market insider Form 4s were net purchases.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in XLO between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 2
- VANGUARD CAPITAL MANAGEMENT LLC$1M
- Caligan Partners LP$943K
Full exits 4
- Point72 Asset Management, L.P.$3M
- STEMPOINT CAPITAL LP$1M
- VANGUARD GROUP INC$804K
- Empery Asset Management, LP$757K
Largest adds
- Bain Capital Life Sciences Investors, LLC$864K
- Stonepine Capital Management, LLC$459K
Largest trims
- Ghisallo Capital Management LLC$597K
- GILEAD SCIENCES, INC.$360K
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| Bain Capital Life Sciences Investors, LLC trimmed | 664,021 | $6M | 18.5% | 2026-Q1 |
| GILEAD SCIENCES, INC. trimmed | 650,389 | $5M | 18.1% | 2026-Q1 |
| Frazier Life Sciences Management, L.P. trimmed | 422,505 | $4M | 11.8% | 2026-Q1 |
| Sio Capital Management, LLC trimmed | 152,464 | $1M | 4.2% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 123,660 | $1M | 3.4% | 2026-Q1 |
| Caligan Partners LP new | 112,128 | $943K | 3.1% | 2026-Q1 |
| Merck & Co., Inc. trimmed | 105,982 | $891K | 3.0% | 2026-Q1 |
| Stonepine Capital Management, LLC trimmed | 64,162 | $540K | 1.8% | 2026-Q1 |
| MORGAN STANLEY trimmed | 57,493 | $484K | 1.6% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 49,566 | $417K | 1.4% | 2026-Q1 |
| AJU IB Investment Co., Ltd. trimmed | 47,695 | $401K | 1.3% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC trimmed | 37,197 | $313K | 1.0% | 2026-Q1 |
| FMR LLC trimmed | 36,558 | $307K | 1.0% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 28,475 | $239K | 0.8% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP trimmed | 16,946 | $143K | 0.5% | 2026-Q1 |
| Velan Capital Investment Management LP trimmed | 14,285 | $120K | 0.4% | 2026-Q1 |
| Ghisallo Capital Management LLC trimmed | 13,800 | $116K | 0.4% | 2026-Q1 |
| STATE STREET CORP trimmed | 13,311 | $112K | 0.4% | 2026-Q1 |
| CWM, LLC new | 4,206 | $35K | 0.1% | 2026-Q1 |
| UBS Group AG added | 4,038 | $34K | 0.1% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 240 | $2K | 0.0% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 210 | $2K | 0.0% | 2026-Q1 |
| ROYAL BANK OF CANADA trimmed | 91 | $1K | 0.0% | 2026-Q1 |
| Key Financial Inc trimmed | 59 | $496 | 0.0% | 2026-Q1 |
| Point72 Asset Management, L.P. new | 4,000,000 | $3M | 8.5% | 2025-Q4 stale |
| STEMPOINT CAPITAL LP new | 2,030,028 | $1M | 4.3% | 2025-Q4 stale |
| TAKEDA PHARMACEUTICAL CO LTD | 1,475,121 | $1M | 4.1% | 2025-Q3 stale |
| VANGUARD GROUP INC | 1,255,692 | $804K | 2.7% | 2025-Q4 stale |
| Empery Asset Management, LP new | 1,183,040 | $757K | 2.5% | 2025-Q4 stale |
| CITADEL ADVISORS LLC added | 436,216 | $279K | 0.9% | 2025-Q4 stale |
| Squarepoint Ops LLC added | 328,794 | $277K | 0.9% | 2025-Q3 stale |
| Trustees of Columbia University in the City of New York | 249,635 | $210K | 0.7% | 2025-Q3 stale |
| BALYASNY ASSET MANAGEMENT L.P. | 198,859 | $168K | 0.6% | 2025-Q3 stale |
| Avantax Planning Partners, Inc. trimmed | 142,338 | $97K | 0.3% | 2025-Q2 stale |
| NORTHERN TRUST CORP | 66,609 | $43K | 0.1% | 2025-Q4 stale |
| TWO SIGMA INVESTMENTS, LP trimmed | 62,032 | $40K | 0.1% | 2025-Q4 stale |
| MILLENNIUM MANAGEMENT LLC added | 51,110 | $37K | 0.1% | 2025-Q1 stale |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 56,081 | $36K | 0.1% | 2025-Q4 stale |
| Scientech Research LLC new | 42,546 | $31K | 0.1% | 2025-Q1 stale |
| ADAR1 Capital Management, LLC added | 40,000 | $29K | 0.1% | 2025-Q1 stale |
| TWO SIGMA SECURITIES, LLC trimmed | 32,130 | $27K | 0.1% | 2025-Q3 stale |
| JANE STREET GROUP, LLC new | 42,080 | $27K | 0.1% | 2025-Q4 stale |
| TWO SIGMA ADVISERS, LP new | 29,689 | $25K | 0.1% | 2025-Q3 stale |
| Aptus Capital Advisors, LLC | 25,000 | $21K | 0.1% | 2025-Q3 stale |
| HRT FINANCIAL LP added | 31,886 | $20K | 0.1% | 2025-Q4 stale |
| SevenBridge Financial Group, LLC | 25,000 | $19K | 0.1% | 2025-Q3 stale |
| Mariner, LLC | 25,000 | $16K | 0.1% | 2025-Q4 stale |
| Steward Partners Investment Advisory, LLC | 20,000 | $14K | 0.0% | 2025-Q1 stale |
| LPL Financial LLC trimmed | 21,000 | $13K | 0.0% | 2025-Q4 stale |
| RAYMOND JAMES FINANCIAL INC | 18,761 | $12K | 0.0% | 2025-Q4 stale |
| XTX Topco Ltd trimmed | 17,304 | $11K | 0.0% | 2025-Q4 stale |
| Tower Research Capital LLC (TRC) added | 15,412 | $10K | 0.0% | 2025-Q2 stale |
| Dunhill Financial, LLC | 10,274 | $7K | 0.0% | 2025-Q4 stale |
| INVESTORS ASSET MANAGEMENT OF GEORGIA INC /GA/ /ADV | 10,000 | $6K | 0.0% | 2025-Q4 stale |
| Pinnacle Financial Group, LLC / IL | 10,000 | $6K | 0.0% | 2025-Q4 stale |
| Federation des caisses Desjardins du Quebec | 3,300 | $3K | 0.0% | 2025-Q3 stale |
| BlackRock, Inc. | 2,037 | $1K | 0.0% | 2025-Q4 stale |
| CITIGROUP INC trimmed | 258 | $217 | 0.0% | 2025-Q3 stale |
| Private Wealth Management Group, LLC | 310 | $199 | 0.0% | 2025-Q4 stale |
| BANK OF AMERICA CORP /DE/ added | 261 | $167 | 0.0% | 2025-Q4 stale |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | 0 | — | 0.0% | 2025-Q2 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.