iBio, Inc. (IBIO) Ownership
IBIO ownership summary
as of October 18, 2026- Institutions
- 65.1% of shares outstanding
- Insiders
- 1.32% of shares outstanding
- Shares outstanding
- 64.3M
- Float
- 45.9M shares available to trade
- Short interest
- 6.56% 4.2M shares short
- Days to cover
- 6.90 short interest down 14.9% vs prior month
- Institutions 65.12%
- Insiders 1.32%
- Other investors 33.56%
IBIO top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Affinity Asset Advisors, LLC | 6.23% | 4.0M | $3.1M | +900,681 (+29.0%) | June 30, 2026 |
| 2 | Cormorant Asset Management, LLC | 5.55% | 3.6M | $2.7M | +3.6M (0.0%) | June 30, 2026 |
| 3 | SILVERARC CAPITAL MANAGEMENT, LLC | 5.47% | 3.5M | $2.7M | +3.3M (+1,457.7%) | June 30, 2026 |
| 4 | Vestal Point Capital LP | 4.04% | 2.6M | $2.0M | +2.6M (0.0%) | June 30, 2026 |
| 5 | Vanguard Capital Management, LLC | 3.26% | 2.1M | $1.6M | +1.0M (+92.8%) | June 30, 2026 |
| 6 | Frazier Life Sciences Management, L.P. | 3.04% | 2.0M | $1.5M | — | June 30, 2026 |
| 7 | Ensign Peak Advisors Inc | 2.85% | 1.8M | $1.4M | +1.8M (0.0%) | June 30, 2026 |
| 8 | Woodline Partners LP | 2.76% | 1.8M | $1.4M | +1.8M (0.0%) | June 30, 2026 |
| 9 | Millennium Management LLC | 2.57% | 1.7M | $1.3M | +101,623 (+6.6%) | June 30, 2026 |
| 10 | Citadel Advisors Llc | 2.15% | 1.4M | $1.1M | +427,600 (+44.7%) | June 30, 2026 |
| 11 | Balyasny Asset Management LLC | 1.82% | 1.2M | $901,588 | +159,938 (+15.8%) | June 30, 2026 |
| 12 | Bank of America Corp | 1.74% | 1.1M | $863,549 | +831,079 (+286.2%) | June 30, 2026 |
| 13 | Ikarian Capital, LLC | 1.49% | 957K | $736,938 | — | June 30, 2026 |
| 14 | Sio Capital Management, LLC | 1.41% | 904K | $696,286 | — | June 30, 2026 |
| 15 | Marshall Wace Asset Management Ltd | 1.41% | 904K | $696,182 | +283,530 (+45.7%) | June 30, 2026 |
| 16 | Geode Capital Management, LLC | 0.78% | 501K | $385,628 | +113,249 (+29.2%) | June 30, 2026 |
| 17 | Walleye Trading Advisors, LLC | 0.78% | 500K | $385,289 | +111,821 (+28.8%) | June 30, 2026 |
| 18 | Squarepoint Ops LLC | 0.78% | 499K | $384,131 | +498,872 (0.0%) | June 30, 2026 |
| 19 | Noesis Capital Management | 0.63% | 405K | $311,850 | +93,500 (+30.0%) | June 30, 2026 |
| 20 | Two Sigma Investments LLC | 0.62% | 401K | $308,514 | −8,191 (−2.0%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 16 holders added 17.6M shares and 1 cut 8,191.
IBIO top mutual fund and ETF holders
11 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Vanguard MStar Total Stk Mkt Idx Invest | 2.28% | 1.5M | $1.1M | — | August 31, 2026 |
| 2 | Fidelity Extended Market Index | 0.40% | 256K | $197,412 | −1,378 (−0.5%) | August 31, 2026 |
| 3 | iShares Micro-Cap ETF | 0.23% | 151K | $116,113 | −1,040 (−0.7%) | September 30, 2026 |
| 4 | Fidelity Total Market Index | 0.13% | 84K | $64,373 | +9,039 (+12.1%) | August 31, 2026 |
| 5 | Fidelity Series Total Market Index | 0.12% | 75K | $57,978 | — | August 31, 2026 |
| 6 | Vanguard MStar Inst Ttl StkMktIdxInstlPl | 0.05% | 30K | $22,781 | — | August 31, 2026 |
| 7 | Vanguard Balanced Index Inv | 0.03% | 21K | $15,909 | — | August 31, 2026 |
| 8 | 1290 VT Micro Cap K | 0.01% | 6,970 | $5,367 | — | August 31, 2026 |
| 9 | Vanguard U.S. Eq Idx £ Acc | 0.01% | 5,460 | $4,204 | — | August 31, 2026 |
| 10 | JHVIT Total Stock Market Index I | <0.01% | 963 | $742 | +309 (+47.2%) | August 31, 2026 |
| 11 | Guggenheim Active Allocation Fund | 0.00% | 4 | $3 | +2 (+100.0%) | May 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
IBIO insider transactions
latest 2| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-03-19 | Felipe Duran | Buy | $2.02 | 24,835 | $50,167 |
| 2026-03-19 | Martin Brenner | Buy | $2.02 | 12,336 | $24,919 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
IBIO shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns IBIO
Institutional investors own 65.1% of iBio's shares and insiders 1.32%. The largest holder is Affinity Asset Advisors, LLC with 6.23% of the shares (4.0M), as of June 30, 2026. Among the top 20 institutions, 16 added shares and 1 reduced their stake in the latest filings. Short interest is 6.56% of the float, or 6.90 days of average trading volume. The share count rose 17,362.2% since 2014.
Related: IBIO analyst forecast, IBIO key metrics. See the IBIO stock overview for the latest quote and news.
IBIO ownership FAQ
Who owns the most iBio stock?
The largest shareholders of iBio are Affinity Asset Advisors, LLC (6.23%), Cormorant Asset Management, LLC (5.55%), SILVERARC CAPITAL MANAGEMENT, LLC (5.47%), Vestal Point Capital LP (4.04%), Vanguard Capital Management, LLC (3.26%).
What percentage of iBio is owned by institutions?
Institutions hold 65.1% of iBio's shares outstanding; insiders hold 1.32%.
Which funds own iBio?
The largest fund holders of iBio are Vanguard MStar Total Stk Mkt Idx Invest (2.28%), Fidelity Extended Market Index (0.40%), iShares Micro-Cap ETF (0.23%), Fidelity Total Market Index (0.13%), Fidelity Series Total Market Index (0.12%).
What is iBio's short interest?
4.2M shares of iBio were sold short, 6.56% of the float; at the average daily volume it would take 6.90 days to cover.
Are insiders buying or selling iBio?
Of the latest 2 reported insider transactions in iBio (since March 19, 2026), 2 were purchases and 0 were sales.
How many shares of iBio are outstanding?
iBio has 64.3M shares outstanding, of which 45.9M are in the public float.