JBIO's three largest insider shareholders as of May 14, 2026 are Venture Partners X, L.P. Sofinnova (TenPercentOwner, 3.76Mn shares), David S. Grayzel (Director, 3.10Mn shares), Venture Fund Xii, L.P. Atlas (TenPercentOwner, 2.33Mn shares).
| Holder | Position | Shares (Direct) | Shares (Indirect) | Report Date |
|---|---|---|---|---|
| Venture Partners X, L.P. Sofinnova | - | 3,758,686 | 0 | 06 Jul, 2021 |
| David S. Grayzel | - | 0 | 3,103,879 | 06 Jul, 2021 |
| Venture Fund Xii, L.P. Atlas | - | 2,327,909 | 0 | 19 Jul, 2022 |
| Asset Management, Lp Cormorant | - | 0 | 2,030,691 | 07 Jul, 2021 |
| Funds Management Llc Fairmount | - | 0 | 1,897,677 | 08 Oct, 2025 |
| Andrew James King | - | 386,113 | 0 | 13 Feb, 2026 |
| Tom Frohlich | Chief Executive Officer | 86,331 | 0 | 13 Feb, 2026 |
| Bradford D. Dahms | Chief Financial Officer | 37,813 | 0 | 13 Feb, 2026 |
| Elizabeth Balta | - | 28,125 | 0 | 13 Feb, 2026 |
| David S. Grayzel | - | 0 | 14,502 | 11 Apr, 2024 |
| Benjamin T Dake | - | 14,252 | 0 | 02 Aug, 2024 |
| Hunter Gillies | Chief Medical Officer | 5,602 | 0 | 14 Jun, 2024 |
| George A Eldridge | - | 5,022 | 0 | 14 Jun, 2024 |
| Ralph Niven | Chief Scientific Officer | 1,609 | 0 | 07 Feb, 2024 |
* Please note that the shares above only reflect shares from the fund portfolio and the institutional portfolio. Shares from the personal portfolio are excluded from this Institutional Ownership Page. See these insiders' latest transactions here on Insider Page.
| Transaction Date | Insider Name | Security Class | Transaction Type | Shares Traded | Price | Shares Remaining | Ownership | Code |
|---|---|---|---|---|---|---|---|---|
| 12 Feb, 2026 | Elizabeth Balta | Common Stock | A | 28,125 | $0.00 | 28,125 | D | A |
| 12 Feb, 2026 | Andrew James King | Common Stock | A | 41,250 | $0.00 | 386,113 | D | A |
| 12 Feb, 2026 | Bradford D. Dahms | Common Stock | A | 37,813 | $0.00 | 37,813 | D | A |
| 12 Feb, 2026 | Tom Frohlich | Common Stock | A | 78,750 | $0.00 | 86,331 | D | A |
| 12 Feb, 2026 | Elizabeth Balta | Stock Option (Right to Buy) | A | 168,750 | $0.00 | 168,750 | D | A |
| 12 Feb, 2026 | Tom Frohlich | Stock Option (Right to Buy) | A | 472,500 | $0.00 | 472,500 | D | A |
| 12 Feb, 2026 | Andrew James King | Stock Option (Right to Buy) | A | 247,500 | $0.00 | 247,500 | D | A |
| 12 Feb, 2026 | Bradford D. Dahms | Stock Option (Right to Buy) | A | 226,875 | $0.00 | 226,875 | D | A |
| 06 Oct, 2025 | Funds Management Llc Fairmount | Common Stock | A | 1,333,126 | $9.14 | 1,897,677 | I | A |
| 06 Oct, 2025 | Funds Management Llc Fairmount | Pre-Funded Warrant (Right to Buy) | A | 855,047 | $9.14 | 855,047 | I | A |
| 14 Jul, 2025 | Bradford D. Dahms | Stock Option (Right to Buy) | A | 526,000 | $0.00 | 526,000 | D | A |
| 16 May, 2025 | Tom Frohlich | Common Stock | A | 6,000 | $7.40 | 6,000 | D | P |
| 29 Apr, 2025 | Funds Management Llc Fairmount | Stock Option (Right to Buy) | A | 23,017 | $0.00 | 23,017 | D | A |
| 29 Apr, 2025 | Eric Dobmeier | Stock Option (Right to Buy) | A | 23,017 | $0.00 | 23,017 | D | A |
| 29 Apr, 2025 | Christopher W. Cain | Stock Option (Right to Buy) | A | 23,017 | $0.00 | 23,017 | D | A |
| 29 Apr, 2025 | Erin Lavelle | Stock Option (Right to Buy) | A | 23,017 | $0.00 | 23,017 | D | A |
| 31 Jul, 2024 | Benjamin T Dake | Common Stock | A | 11,454 | $1.74 | 12,745 | D | M |
| 01 Aug, 2024 | Benjamin T Dake | Common Stock | A | 1,507 | $1.74 | 14,252 | D | M |
| 31 Jul, 2024 | Benjamin T Dake | Stock Option (Right to Buy) | D | 906 | $0.00 | 0 | D | M |
| 31 Jul, 2024 | Benjamin T Dake | Stock Option (Right to Buy) | D | 10,548 | $0.00 | 1,507 | D | M |