BillionToOne, Inc. (BLLN) Ownership
BLLN ownership summary
as of October 18, 2026- Institutions
- 45.5% of shares outstanding
- Insiders
- 28.36% of shares outstanding
- Shares outstanding
- 42.6M
- Float
- 28.8M shares available to trade
- Short interest
- 10.78% 2.8M shares short
- Days to cover
- 4.40 short interest up 7.3% vs prior month
- Institutions 45.55%
- Insiders 28.36%
- Other investors 26.09%
BLLN top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Adams Street Partners LLC | 3.63% | 1.7M | $167.9M | — | June 30, 2026 |
| 2 | T. Rowe Price Associates, Inc. | 2.14% | 1.0M | $99.1M | +272,804 (+37.0%) | June 30, 2026 |
| 3 | Baillie Gifford & Co Limited. | 1.91% | 901K | $88.4M | −358,573 (−28.5%) | June 30, 2026 |
| 4 | Vanguard Portfolio Management, LLC | 1.78% | 841K | $82.5M | +689,757 (+456.1%) | June 30, 2026 |
| 5 | Amvescap Plc. | 1.77% | 836K | $82.0M | +429,102 (+105.6%) | June 30, 2026 |
| 6 | Vanguard Capital Management, LLC | 1.69% | 799K | $78.4M | +617,005 (+338.2%) | June 30, 2026 |
| 7 | Neuberger Berman Group LLC | 1.62% | 764K | $75.0M | +55,001 (+7.8%) | June 30, 2026 |
| 8 | BAMCO Inc | 1.57% | 742K | $72.8M | +608 (+0.1%) | June 30, 2026 |
| 9 | Wasatch Advisors LP | 1.10% | 518K | $50.8M | +148,446 (+40.2%) | June 30, 2026 |
| 10 | Millennium Management LLC | 0.90% | 425K | $41.7M | +425,032 (0.0%) | June 30, 2026 |
| 11 | Fuller & Thaler Asset Management Inc | 0.89% | 419K | $41.1M | +418,565 (0.0%) | June 30, 2026 |
| 12 | Emerald Advisers, LLC | 0.80% | 376K | $36.9M | +136,296 (+56.9%) | June 30, 2026 |
| 13 | Next Century Growth Investors LLC | 0.77% | 364K | $35.8M | +273,903 (+302.4%) | June 30, 2026 |
| 14 | UBS Group AG | 0.73% | 344K | $33.8M | +222,683 (+183.1%) | June 30, 2026 |
| 15 | JPMorgan Chase & Co | 0.72% | 340K | $33.4M | +57,231 (+20.2%) | June 30, 2026 |
| 16 | Ameriprise Financial Inc | 0.68% | 321K | $31.5M | +100,577 (+45.7%) | June 30, 2026 |
| 17 | Oberweis Asset Management Inc | 0.63% | 299K | $29.3M | +299,030 (0.0%) | June 30, 2026 |
| 18 | Wells Fargo & Co | 0.58% | 272K | $26.6M | +270,446 (+24,408.5%) | June 30, 2026 |
| 19 | AllianceBernstein L.P. | 0.56% | 262K | $25.7M | +38,852 (+17.4%) | June 30, 2026 |
| 20 | NAPEAN TRADING AND INVESTMENT CO (SINGAPORE) PTE Ltd. | 0.49% | 233K | $22.9M | — | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 17 holders added 4.5M shares and 1 cut 359K.
BLLN top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Vanguard MStar Total Stk Mkt Idx Invest | 1.54% | 726K | $71.2M | −952 (−0.1%) | August 31, 2026 |
| 2 | Invesco Discovery A | 1.13% | 531K | $52.1M | +43,870 (+9.0%) | August 31, 2026 |
| 3 | Vanguard Small Cap Index | 1.11% | 524K | $51.4M | −17 (−0.0%) | August 31, 2026 |
| 4 | T. Rowe Price Health Sciences | 0.65% | 309K | $30.3M | −12,600 (−3.9%) | August 31, 2026 |
| 5 | T. Rowe Price Small-Cap Stock | 0.65% | 308K | $30.2M | +259,699 (+535.9%) | August 31, 2026 |
| 6 | Baron Discovery Institutional | 0.61% | 287K | $28.1M | — | September 30, 2026 |
| 7 | Oberweis Small-Cap Opportunities | 0.56% | 264K | $25.9M | +264,300 (0.0%) | June 30, 2026 |
| 8 | Adams Street Private Eq Navigator LLC M | 0.52% | 247K | $24.2M | — | June 30, 2026 |
| 9 | Edinburgh Worldwide Ord | 0.51% | 240K | $23.5M | — | June 30, 2026 |
| 10 | Wasatch Small Cap Growth Investor | 0.43% | 204K | $20.1M | +27,240 (+15.4%) | June 30, 2026 |
| 11 | T. Rowe Price Instl Small-Cap Stock | 0.36% | 169K | $16.6M | +144,339 (+592.1%) | August 31, 2026 |
| 12 | T. Rowe Price New Horizons | 0.35% | 167K | $16.4M | +28,028 (+20.2%) | August 31, 2026 |
| 13 | Vanguard MStar Small Cap Value Index | 0.35% | 167K | $16.3M | +130 (+0.1%) | August 31, 2026 |
| 14 | Invesco Main Street Small Cap R6 | 0.35% | 166K | $16.3M | +165,711 (0.0%) | August 31, 2026 |
| 15 | Lord Abbett Developing Growth A | 0.32% | 151K | $14.8M | +151,245 (0.0%) | July 31, 2026 |
| 16 | Vanguard MStar Small Cap Growth Indx Inv | 0.32% | 150K | $14.7M | −1,277 (−0.8%) | August 31, 2026 |
| 17 | Alger Small Cap Focus I | 0.31% | 144K | $14.1M | +36,448 (+33.8%) | July 31, 2026 |
| 18 | JPMorgan Small Cap Growth A | 0.28% | 133K | $13.0M | −3,910 (−2.9%) | August 31, 2026 |
| 19 | Baillie Gifford US Growth Ord | 0.26% | 124K | $12.2M | −29,902 (−19.4%) | July 31, 2026 |
| 20 | Schwab US Small-Cap ETF™ | 0.25% | 117K | $11.5M | +72 (+0.1%) | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
BLLN shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns BLLN
Institutional investors own 45.5% of BillionToOne's shares and insiders 28.36%. The largest holder is Adams Street Partners LLC with 3.63% of the shares (1.7M), as of June 30, 2026. Among the top 20 institutions, 17 added shares and 1 reduced their stake in the latest filings. Short interest is 10.78% of the float, or 4.40 days of average trading volume. The share count rose 358.0% since 2023.
Related: BLLN analyst forecast, BLLN key metrics. See the BLLN stock overview for the latest quote and news.
BLLN ownership FAQ
Who owns the most BillionToOne stock?
The largest shareholders of BillionToOne are Adams Street Partners LLC (3.63%), T. Rowe Price Associates, Inc. (2.14%), Baillie Gifford & Co Limited. (1.91%), Vanguard Portfolio Management, LLC (1.78%), Amvescap Plc. (1.77%).
What percentage of BillionToOne is owned by institutions?
Institutions hold 45.5% of BillionToOne's shares outstanding; insiders hold 28.36%.
Which funds own BillionToOne?
The largest fund holders of BillionToOne are Vanguard MStar Total Stk Mkt Idx Invest (1.54%), Invesco Discovery A (1.13%), Vanguard Small Cap Index (1.11%), T. Rowe Price Health Sciences (0.65%), T. Rowe Price Small-Cap Stock (0.65%).
What is BillionToOne's short interest?
2.8M shares of BillionToOne were sold short, 10.78% of the float; at the average daily volume it would take 4.40 days to cover.
How many shares of BillionToOne are outstanding?
BillionToOne has 42.6M shares outstanding, of which 28.8M are in the public float.