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 Sep 30, 2025
Ownership Breakdown
106
Institutional Holders
▲ 18 vs Q2
$353.55M
Total Inst. Value
▲ $204.63M vs Q2
14.67M
Shares Outstanding
freeFloat 73.96%
10.50M
13F Shares Held
▲ 61,711 vs Q2
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
Q3 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% | $60.21B | Nov 14, 2025 | — held |
PERCEPTIVE ADVISORS LLC biological products, (no diagnostic substances) | 1.33M | 8.58% | 8.58% | $44.72B | Nov 14, 2025 | ▲ 349.8K |
SANOFI biological products, (no diagnostic substances) | 1.16M | 7.49% | 7.49% | $39.00B | Nov 4, 2025 | — held |
HIGHTOWER ADVISORS, LLC biological products, (no diagnostic substances) | 871.8K | 5.64% | 5.64% | $29.36B | Nov 7, 2025 | — held |
BLACKROCK, INC. biological products, (no diagnostic substances) | 684.7K | 4.43% | 4.43% | $23.06B | Nov 12, 2025 | ▼ 44.0K |
VANGUARD GROUP INC biological products, (no diagnostic substances) | 594.9K | 3.85% | 3.85% | $20.04B | Nov 7, 2025 | ▼ 3.5K |
MORGAN STANLEY biological products, (no diagnostic substances) | 442.9K | 2.86% | 2.86% | $14.92B | May 27, 2026 | ▲ 415.0K |
SOFINNOVA INVESTMENTS, INC. biological products, (no diagnostic substances) | 440.1K | 2.85% | 2.85% | $14.82B | Nov 14, 2025 | ▼ 268.6K |
WOODLINE PARTNERS LP biological products, (no diagnostic substances) | 336.6K | 2.18% | 2.18% | $11.34B | Nov 14, 2025 | ▼ 326.3K |
MILLENNIUM MANAGEMENT LLC biological products, (no diagnostic substances) | 297.8K | 1.93% | 1.93% | $10.03B | Nov 14, 2025 | ▲ 22.0K |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
13
Increased
+1.09M shares7
New Positions
first time holders22
Decreased
−1.23M shares0
Sold Out
fully exitedNet shares change (top 50)
138.7K
+1.09M / −1.23M
Net new holders
-2
7 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 71.5% of total shares outstanding. Company insiders own approximately 26.04%, while retail and public investors account for the remaining 2.41%.
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 September 30, 2025.
A total of 106 institutional investors currently hold INBX stock, with a combined institutional value of approximately $353,550,914 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 71.5% 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 September 30, 2025.