Arrowhead Pharmaceuticals, Inc. (ARWR) Ownership
ARWR ownership summary
as of October 18, 2026- Institutions
- 85.2% of shares outstanding
- Insiders
- 3.66% of shares outstanding
- Shares outstanding
- 141.3M
- Float
- 122.4M shares available to trade
- Short interest
- 10.60% 10.8M shares short
- Days to cover
- 4.77 short interest up 16.0% vs prior month
- Institutions 85.25%
- Insiders 3.66%
- Other investors 11.10%
ARWR top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | BlackRock Inc | 10.50% | 14.8M | $829.0M | −3.3M (−18.3%) | June 30, 2026 |
| 2 | venBio Select Advisor LLC | 8.04% | 11.4M | $634.8M | +655,556 (+6.1%) | June 30, 2026 |
| 3 | FMR Inc | 5.69% | 8.0M | $449.4M | +773,152 (+10.6%) | June 30, 2026 |
| 4 | Vanguard Portfolio Management, LLC | 4.50% | 6.4M | $355.0M | −794,781 (−11.1%) | June 30, 2026 |
| 5 | Vanguard Capital Management, LLC | 4.33% | 6.1M | $341.6M | +78,537 (+1.3%) | June 30, 2026 |
| 6 | State Street Corp | 4.03% | 5.7M | $318.3M | −801,490 (−12.3%) | June 30, 2026 |
| 7 | NORGES BANK | 2.76% | 3.9M | $217.8M | +2.2M (+128.6%) | June 30, 2026 |
| 8 | Amvescap Plc. | 2.75% | 3.9M | $217.1M | +603,329 (+18.4%) | June 30, 2026 |
| 9 | Geode Capital Management, LLC | 2.50% | 3.5M | $197.4M | −748,216 (−17.5%) | June 30, 2026 |
| 10 | Fred Alger Management, LLC | 2.34% | 3.3M | $184.6M | −40,574 (−1.2%) | June 30, 2026 |
| 11 | Baker Bros Advisors LP | 1.41% | 2.0M | $111.4M | — | June 30, 2026 |
| 12 | Siren, L.L.C. | 1.21% | 1.7M | $95.9M | +100,000 (+6.2%) | June 30, 2026 |
| 13 | Vestal Point Capital LP | 1.11% | 1.6M | $88.0M | −700,000 (−30.8%) | June 30, 2026 |
| 14 | HHG PLC | 1.02% | 1.4M | $80.3M | +156,544 (+12.2%) | March 31, 2026 |
| 15 | Deerfield Management Co | 0.98% | 1.4M | $77.6M | −184,242 (−11.7%) | June 30, 2026 |
| 16 | First Trust Advisors L.P. | 0.96% | 1.4M | $75.6M | +1.2M (+807.1%) | June 30, 2026 |
| 17 | Driehaus Capital Management LLC | 0.96% | 1.4M | $75.5M | +160,221 (+13.5%) | June 30, 2026 |
| 18 | Jupiter Topco LLC | 0.86% | 1.2M | $68.3M | +1.2M (0.0%) | June 30, 2026 |
| 19 | Northern Trust Corp | 0.84% | 1.2M | $66.7M | −462,969 (−28.0%) | June 30, 2026 |
| 20 | Dimensional Fund Advisors, Inc. | 0.84% | 1.2M | $66.1M | +573,077 (+94.2%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 11 holders added 7.7M shares and 8 cut 7.1M.
ARWR top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | iShares Core S&P Mid-Cap ETF | 3.56% | 5.0M | $281.3M | −1,800 (−0.0%) | September 30, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 3.01% | 4.3M | $237.9M | −4,734 (−0.1%) | August 31, 2026 |
| 3 | Vanguard Small Cap Index | 2.14% | 3.0M | $168.9M | −57,777 (−1.9%) | September 30, 2026 |
| 4 | Fidelity Growth Company Fund | 1.84% | 2.6M | $145.5M | +51,300 (+2.0%) | August 31, 2026 |
| 5 | State Street® SPDR® S&P® Biotech ETF | 1.27% | 1.8M | $100.6M | −34,250 (−1.9%) | September 30, 2026 |
| 6 | Invesco S&P MidCap Momentum ETF | 1.27% | 1.8M | $100.6M | — | September 30, 2026 |
| 7 | Vanguard MStar Small Cap Growth Indx Inv | 1.19% | 1.7M | $94.0M | −84,908 (−4.8%) | September 30, 2026 |
| 8 | State Street® SPDR® S&P MIDCAP 400® ETF | 0.74% | 1.0M | $58.4M | +14,314 (+1.4%) | September 30, 2026 |
| 9 | iShares Biotechnology ETF | 0.73% | 1.0M | $58.0M | −7,856 (−0.8%) | September 30, 2026 |
| 10 | Invesco Discovery A | 0.67% | 940K | $52.5M | +46,497 (+5.2%) | August 31, 2026 |
| 11 | iShares S&P Mid-Cap 400 Growth ETF | 0.58% | 815K | $45.6M | −870 (−0.1%) | September 30, 2026 |
| 12 | Alger Focus Equity I | 0.54% | 763K | $42.6M | −2,676 (−0.3%) | July 31, 2026 |
| 13 | State Street SPDR Port S&P 400 Md CpETF | 0.53% | 747K | $41.7M | −1,048 (−0.1%) | September 30, 2026 |
| 14 | Fidelity Growth Company K6 | 0.53% | 745K | $41.7M | +14,600 (+2.0%) | August 31, 2026 |
| 15 | Schwab US Small-Cap ETF™ | 0.53% | 743K | $41.6M | +495 (+0.1%) | September 30, 2026 |
| 16 | Fidelity Extended Market Index | 0.49% | 685K | $38.3M | −6,654 (−1.0%) | August 31, 2026 |
| 17 | Fidelity Series Growth Company | 0.44% | 618K | $34.5M | +6,200 (+1.0%) | August 31, 2026 |
| 18 | Hood River Small-Cap Growth Instl | 0.40% | 572K | $32.0M | −6,492 (−1.1%) | June 30, 2026 |
| 19 | iShares Russell Mid-Cap ETF | 0.39% | 558K | $31.2M | +1,026 (+0.2%) | September 30, 2026 |
| 20 | Fidelity Mid Cap Index | 0.36% | 514K | $28.7M | +1,807 (+0.4%) | August 31, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
ARWR insider transactions
latest 20| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-04-23 | James C Hamilton | Sell | $75.00 | 10,000 | $750,000 |
| 2026-04-22 | Daniel Joseph Apel | Sell | $71.35 | 13,095 | $934,328 |
| 2026-03-05 | James C Hamilton | Sell | $64.19 | 10,000 | $641,900 |
| 2026-01-05 | James C Hamilton | Sell | $63.11 | 40,164 | $2.5M |
| 2026-01-05 | Patrick O'brien | Sell | $63.11 | 49,493 | $3.1M |
| 2026-01-02 | Christopher Richard Anzalone | Sell | $66.10 | 13,187 | $871,661 |
| 2025-12-29 | Christopher Richard Anzalone | Sell | $69.13 | 51,726 | $3.6M |
| 2025-12-26 | Mauro Ferrari | Sell | $70.00 | 7,530 | $527,100 |
| 2025-12-22 | Christopher Richard Anzalone | Sell | $68.44 | 12,586 | $861,386 |
| 2025-12-19 | Victoria Vakiener | Sell | $67.68 | 10,040 | $679,507 |
| 2025-12-19 | William D Waddill | Sell | $67.65 | 8,367 | $566,028 |
| 2025-12-19 | Christopher Richard Anzalone | Sell | $67.66 | 13,445 | $909,689 |
| 2025-12-19 | Adeoye Y Olukotun | Sell | $67.66 | 10,000 | $676,600 |
| 2025-12-17 | Christopher Richard Anzalone | Sell | $64.04 | 85,000 | $5.4M |
| 2025-12-16 | Christopher Richard Anzalone | Sell | $62.58 | 54,298 | $3.4M |
| 2025-12-15 | Christopher Richard Anzalone | Sell | $68.85 | 130,000 | $9.0M |
| 2025-12-05 | Michael S Perry | Sell | $61.03 | 16,250 | $991,738 |
| 2025-11-28 | Mauro Ferrari | Sell | $56.39 | 8,750 | $493,412 |
| 2025-10-01 | James C Hamilton | Sell | $35.00 | 20,000 | $700,000 |
| 2025-09-12 | James C Hamilton | Sell | $30.00 | 15,000 | $450,000 |
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.
ARWR shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns ARWR
Institutional investors own 85.2% of Arrowhead Pharmaceuticals's shares and insiders 3.66%. The largest holder is BlackRock Inc with 10.50% of the shares (14.8M), as of June 30, 2026. Among the top 20 institutions, 11 added shares and 8 reduced their stake in the latest filings. Short interest is 10.60% of the float, or 4.77 days of average trading volume. The share count rose 157.3% since 2014.
Related: ARWR analyst forecast, ARWR key metrics. See the ARWR stock overview for the latest quote and news.
ARWR ownership FAQ
Who owns the most Arrowhead Pharmaceuticals stock?
The largest shareholders of Arrowhead Pharmaceuticals are BlackRock Inc (10.50%), venBio Select Advisor LLC (8.04%), FMR Inc (5.69%), Vanguard Portfolio Management, LLC (4.50%), Vanguard Capital Management, LLC (4.33%).
What percentage of Arrowhead Pharmaceuticals is owned by institutions?
Institutions hold 85.2% of Arrowhead Pharmaceuticals's shares outstanding; insiders hold 3.66%.
Which funds own Arrowhead Pharmaceuticals?
The largest fund holders of Arrowhead Pharmaceuticals are iShares Core S&P Mid-Cap ETF (3.56%), Vanguard MStar Total Stk Mkt Idx Invest (3.01%), Vanguard Small Cap Index (2.14%), Fidelity Growth Company Fund (1.84%), State Street® SPDR® S&P® Biotech ETF (1.27%).
What is Arrowhead Pharmaceuticals's short interest?
10.8M shares of Arrowhead Pharmaceuticals were sold short, 10.60% of the float; at the average daily volume it would take 4.77 days to cover.
Are insiders buying or selling Arrowhead Pharmaceuticals?
Of the latest 20 reported insider transactions in Arrowhead Pharmaceuticals (since September 12, 2025), 0 were purchases and 20 were sales.
How many shares of Arrowhead Pharmaceuticals are outstanding?
Arrowhead Pharmaceuticals has 141.3M shares outstanding, of which 122.4M are in the public float.