Inhibrx Biosciences, Inc.
Inhibrx Biosciences, Inc. (INBX) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · INBX · as of Mar 31, 2025
Ownership Breakdown
96
Institutional Holders
▼ 12 vs Q4
$151.46M
Total Inst. Value
▼ $20.47M vs Q4
14.67M
Shares Outstanding
freeFloat 73.96%
10.83M
13F Shares Held
▼ 339,125 vs Q4
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
INBX largest shareholders · institutional ownership
Q1 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
VIKING GLOBAL INVESTORS LP biological products, (no diagnostic substances) | 1.79M | 11.56% | 11.56% | $25.01B | May 15, 2025 | — held |
SANOFI biological products, (no diagnostic substances) | 1.16M | 7.49% | 7.49% | $16.20B | May 6, 2025 | — held |
PERCEPTIVE ADVISORS LLC biological products, (no diagnostic substances) | 1.06M | 6.88% | 6.88% | $14.89B | Aug 6, 2025 | — held |
HIGHTOWER ADVISORS, LLC biological products, (no diagnostic substances) | 871.8K | 5.64% | 5.64% | $12.20B | May 13, 2025 | ▲ 90.0K |
BLACKROCK, INC. biological products, (no diagnostic substances) | 832.7K | 5.38% | 5.38% | $11.65B | May 2, 2025 | ▲ 925 |
SOFINNOVA INVESTMENTS, INC. biological products, (no diagnostic substances) | 697.9K | 4.51% | 4.51% | $9.76B | May 15, 2025 | ▲ 170.7K |
VANGUARD GROUP INC biological products, (no diagnostic substances) | 588.3K | 3.80% | 3.80% | $8.23B | May 9, 2025 | ▼ 19.4K |
PFM HEALTH SCIENCES, LP biological products, (no diagnostic substances) | 439.3K | 2.84% | 2.84% | $6.15B | May 15, 2025 | ▲ 303.7K |
WOODLINE PARTNERS LP biological products, (no diagnostic substances) | 358.4K | 2.32% | 2.32% | $5.01B | May 15, 2025 | NEW |
SLOTNIK CAPITAL, LLC biological products, (no diagnostic substances) | 287.0K | 1.86% | 1.86% | $4.01B | May 13, 2025 | ▼ 101.0K |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q1 2025 vs prior quarter
Q1 2025
11
Increased
+647.9K shares6
New Positions
first time holders17
Decreased
−417.0K shares0
Sold Out
fully exitedNet shares change (top 50)
+230.8K
+647.9K / −417.0K
Net new holders
+0
6 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
INBX insider trading · insider activity
Source: SEC Form 4
Insiders have been primarily selling shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
5
Buy transactions
0
Sell transactions
0.00
Buy/Sell ratio
$0M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
Vuori Kristiina MD director | Jun 3, 2026 | Award | 15,000 | $95.22 | $1.43M | 15.0K | Form 4 ↗ |
Kayyem Jon Faiz director | Jun 3, 2026 | Award | 15,000 | $95.22 | $1.43M | 15.0K | Form 4 ↗ |
FORSYTH DOUGLAS director | Jun 3, 2026 | Award | 15,000 | $95.22 | $1.43M | 15.0K | Form 4 ↗ |
MANHARD KIMBERLY director | Jun 3, 2026 | Award | 15,000 | $95.22 | $1.43M | 15.0K | Form 4 ↗ |
Matly David President | Apr 24, 2026 | Award | 50,000 | $129.06 | $6.45M | 50.0K | Form 4 ↗ |
VIKING GLOBAL INVESTORS LP 10 percent owner | Oct 7, 2025 | Sale | 308,643 | $32.25 | $9.95M | 1.27M | Form 4 ↗ |
VIKING GLOBAL INVESTORS LP 10 percent owner | Oct 7, 2025 | Sale | 25,042 | $32.25 | $807.6K | 102.9K | Form 4 ↗ |
VIKING GLOBAL INVESTORS LP 10 percent owner | Oct 7, 2025 | Sale | 16,315 | $32.25 | $526.2K | 67.0K | Form 4 ↗ |
MANHARD KIMBERLY director | May 28, 2025 | Award | 15,000 | $12.91 | $193.7K | 15.0K | Form 4 ↗ |
Vuori Kristiina MD director | May 28, 2025 | Award | 15,000 | $12.91 | $193.7K | 15.0K | Form 4 ↗ |
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Inhibrx Biosciences, Inc. (INBX) is primarily owned by institutional investors, who hold approximately 73.8% of total shares outstanding. Company insiders own approximately 26.04%, while retail and public investors account for the remaining 0.17%.
The largest institutional shareholder of Inhibrx Biosciences, Inc. is VIKING GLOBAL INVESTORS LP, holding approximately 1.79 million shares — equal to 11.56% of outstanding shares — as of March 31, 2025.
A total of 96 institutional investors currently hold INBX stock, with a combined institutional value of approximately $151,457,810 as of the most recent 13F filing period.
Frequently asked questions
INBX ownershipInhibrx Biosciences, Inc. (INBX) is primarily owned by institutional investors, who hold approximately 73.8% of shares. The largest shareholder is VIKING GLOBAL INVESTORS LP with a 11.56% stake. Company insiders hold 26.04%. Data sourced from SEC Form 13F as of March 31, 2025.