AC Immune SA (ACIU) Ownership
ACIU ownership summary
as of October 18, 2026- Institutions
- 24.3% of shares outstanding
- Insiders
- 38.09% of shares outstanding
- Shares outstanding
- 99.4M
- Float
- 39.2M shares available to trade
- Short interest
- 7.59% 3.5M shares short
- Days to cover
- 21.42 short interest up 1.4% vs prior month
- Institutions 24.34%
- Insiders 38.09%
- Other investors 37.57%
ACIU top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Bvf Inc | 19.94% | 19.8M | $47.4M | — | June 30, 2026 |
| 2 | Wells Fargo & Co | 1.01% | 1.0M | $2.4M | −243 (−0.0%) | June 30, 2026 |
| 3 | Renaissance Technologies Corp | 0.84% | 840K | $2.0M | +215,760 (+34.6%) | June 30, 2026 |
| 4 | Millennium Management LLC | 0.78% | 774K | $1.8M | −19,063 (−2.4%) | June 30, 2026 |
| 5 | BlackRock Inc | 0.52% | 519K | $1.2M | −5,004 (−1.0%) | June 30, 2026 |
| 6 | Dimensional Fund Advisors, Inc. | 0.34% | 340K | $812,796 | −50,083 (−12.8%) | June 30, 2026 |
| 7 | Arrowstreet Capital Limited Partnership | 0.23% | 233K | $556,758 | −172,705 (−42.6%) | June 30, 2026 |
| 8 | Citadel Advisors Llc | 0.21% | 208K | $496,178 | −59,627 (−22.3%) | June 30, 2026 |
| 9 | Morgan Stanley - Brokerage Accounts | 0.13% | 132K | $315,038 | +42,562 (+47.7%) | June 30, 2026 |
| 10 | Two Sigma Investments LLC | 0.10% | 103K | $245,752 | +63,734 (+163.0%) | June 30, 2026 |
| 11 | Deeter Investments LLP | 0.10% | 100K | $239,000 | — | March 31, 2026 |
| 12 | Qube Research & Technologies | 0.09% | 92K | $220,719 | +92,351 (0.0%) | June 30, 2026 |
| 13 | UBS Group AG | 0.09% | 86K | $204,617 | −16,015 (−15.8%) | June 30, 2026 |
| 14 | Geode Capital Management, LLC | 0.06% | 62K | $147,831 | −1,747 (−2.7%) | June 30, 2026 |
| 15 | Susquehanna International Group, LLP | 0.05% | 53K | $127,552 | −35,893 (−40.2%) | June 30, 2026 |
| 16 | Jump Financial LLC | 0.02% | 24K | $57,513 | +12,939 (+116.3%) | June 30, 2026 |
| 17 | Jane Street Group LLC | 0.02% | 19K | $46,545 | −38,221 (−66.2%) | June 30, 2026 |
| 18 | Verdad Advisers, LP | 0.02% | 16K | $38,957 | +16,300 (0.0%) | June 30, 2026 |
| 19 | China Universal Asset Mgmt Co.Ltd | 0.02% | 16K | $38,711 | −1,655 (−9.3%) | June 30, 2026 |
| 20 | The Goldman Sachs Group Inc | 0.01% | 14K | $34,648 | −7,135 (−33.0%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 6 holders added 444K shares and 12 cut 407K.
ACIU top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | iShares Biotechnology ETF | 0.48% | 478K | $1.1M | −3,624 (−0.8%) | September 30, 2026 |
| 2 | Monega ARIAD Innovation R | 0.09% | 92K | $220,738 | — | August 31, 2026 |
| 3 | Dimensional US Small Cap ETF | 0.08% | 81K | $192,971 | — | September 30, 2026 |
| 4 | iShares Nasdaq US Biotech ETF USD Acc | 0.08% | 80K | $191,661 | +696 (+0.9%) | September 30, 2026 |
| 5 | Fidelity Nasdaq Composite Index | 0.07% | 70K | $166,942 | — | August 31, 2026 |
| 6 | DFA US Small Cap I | 0.05% | 45K | $108,477 | — | August 31, 2026 |
| 7 | DFA US Micro Cap I | 0.04% | 44K | $105,332 | — | August 31, 2026 |
| 8 | Top Class Healthcare FI | 0.04% | 40K | $95,600 | — | August 31, 2026 |
| 9 | China Universal NASDAQ Bio-Tch ETF(QDII) | 0.02% | 16K | $38,711 | −165 (−1.0%) | June 30, 2026 |
| 10 | DFA US Vector Equity I | 0.02% | 16K | $37,812 | — | August 31, 2026 |
| 11 | Dimensional Global Small Coms USD Acc | 0.01% | 12K | $29,165 | — | August 31, 2026 |
| 12 | Dimensional World Equity GBP Acc | 0.01% | 12K | $28,615 | — | August 31, 2026 |
| 13 | Dimensional Gl Cor Eq LC ESG Sc USD A | 0.01% | 9,976 | $23,843 | — | August 31, 2026 |
| 14 | Dimensional International Core Eq Acc | 0.01% | 9,822 | $23,475 | — | August 31, 2026 |
| 15 | JNL/DFA US Small Cap A | 0.01% | 7,966 | $19,039 | — | June 30, 2026 |
| 16 | Dimensional US Core Equity 2 ETF | 0.01% | 7,863 | $18,793 | — | September 30, 2026 |
| 17 | Dimensional World Allc 60/40 GBP Acc | 0.01% | 7,854 | $18,771 | — | August 31, 2026 |
| 18 | Invesco Nasdaq Biotechnology ETF | 0.01% | 7,184 | $17,170 | +322 (+4.7%) | September 30, 2026 |
| 19 | Dimensional US Sm Company EUR Acc | 0.01% | 7,000 | $16,730 | — | August 31, 2026 |
| 20 | Dimensional US Core Equity 1 ETF | 0.01% | 5,748 | $13,738 | — | September 24, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
ACIU shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns ACIU
Institutional investors own 24.3% of AC Immune's shares and insiders 38.09%. The largest holder is Bvf Inc with 19.94% of the shares (19.8M), as of June 30, 2026. Among the top 20 institutions, 6 added shares and 12 reduced their stake in the latest filings. Short interest is 7.59% of the float, or 21.42 days of average trading volume. The share count rose 86.8% since 2014.
Related: ACIU analyst forecast, ACIU key metrics. See the ACIU stock overview for the latest quote and news.
ACIU ownership FAQ
Who owns the most AC Immune stock?
The largest shareholders of AC Immune are Bvf Inc (19.94%), Wells Fargo & Co (1.01%), Renaissance Technologies Corp (0.84%), Millennium Management LLC (0.78%), BlackRock Inc (0.52%).
What percentage of AC Immune is owned by institutions?
Institutions hold 24.3% of AC Immune's shares outstanding; insiders hold 38.09%.
Which funds own AC Immune?
The largest fund holders of AC Immune are iShares Biotechnology ETF (0.48%), Monega ARIAD Innovation R (0.09%), Dimensional US Small Cap ETF (0.08%), iShares Nasdaq US Biotech ETF USD Acc (0.08%), Fidelity Nasdaq Composite Index (0.07%).
What is AC Immune's short interest?
3.5M shares of AC Immune were sold short, 7.59% of the float; at the average daily volume it would take 21.42 days to cover.
How many shares of AC Immune are outstanding?
AC Immune has 99.4M shares outstanding, of which 39.2M are in the public float.