SEC Form 4 · Updated Daily
ATTO
Insider and institutional ownership derived from SEC Form 4 filings. Click any owner to see their holdings across every company they’ve filed on, and how their position has changed over time.
Current Reporting Owners
| Owner | Role | Shares Owned | As Of | Last Activity |
|---|---|---|---|---|
| GOLDMAN SACHS & CO. LLC | Reporting Owner | 3,020,632 | 2026-08-06 | P |
| GOLDMAN SACHS GROUP INC | Reporting Owner | 3,020,632 | 2026-08-06 | P |
| GOLDMAN SACHS ASSET MANAGEMENT, L.P. | Reporting Owner | 3,020,632 | 2026-08-06 | P |
| Broad Street Principal Investments, L.L.C. | Reporting Owner | 3,020,632 | 2026-08-06 | P |
| West Street Life Sciences I, L.P. | Reporting Owner | 3,020,632 | 2026-08-06 | P |
| WSLS EMP OFFSHORE INVESTMENTS, L.P. | Reporting Owner | 3,020,632 | 2026-08-06 | P |
| WSLS OFFSHORE INVESTMENTS, SLP | Reporting Owner | 3,020,632 | 2026-08-06 | P |
| WSLS EMP ONSHORE INVESTMENTS, L.P. | Reporting Owner | 3,020,632 | 2026-08-06 | P |
| Sanofi | 10%+ Owner | 1,082,855 | 2026-08-06 | P |
Recent Filings
| Date | Owner | Activity | Shares | Price | Owned After |
|---|---|---|---|---|---|
| 2026-08-06 | WSLS EMP ONSHORE INVESTMENTS, L.P. | Conversion (derivative) | 4,445,275 | $0.00 | 0 |
| 2026-08-06 | WSLS EMP ONSHORE INVESTMENTS, L.P. | Conversion (derivative) | 18,181,830 | $0.00 | 0 |
| 2026-08-06 | WSLS EMP ONSHORE INVESTMENTS, L.P. | Open-market buy | 500,000 | $17.00 | 3,020,632 |
| 2026-08-06 | WSLS EMP ONSHORE INVESTMENTS, L.P. | Conversion | 478,498 | $0.00 | 2,520,632 |
| 2026-08-06 | WSLS EMP ONSHORE INVESTMENTS, L.P. | Conversion | 1,957,134 | $0.00 | 2,042,134 |
| 2026-08-06 | WSLS EMP OFFSHORE INVESTMENTS, L.P. | Conversion (derivative) | 4,445,275 | $0.00 | 0 |
| 2026-08-06 | WSLS EMP OFFSHORE INVESTMENTS, L.P. | Conversion (derivative) | 18,181,830 | $0.00 | 0 |
| 2026-08-06 | WSLS EMP OFFSHORE INVESTMENTS, L.P. | Open-market buy | 500,000 | $17.00 | 3,020,632 |
| 2026-08-06 | WSLS EMP OFFSHORE INVESTMENTS, L.P. | Conversion | 478,498 | $0.00 | 2,520,632 |
| 2026-08-06 | WSLS EMP OFFSHORE INVESTMENTS, L.P. | Conversion | 1,957,134 | $0.00 | 2,042,134 |
| 2026-08-06 | West Street Life Sciences I, L.P. | Conversion (derivative) | 4,445,275 | $0.00 | 0 |
| 2026-08-06 | West Street Life Sciences I, L.P. | Conversion (derivative) | 18,181,830 | $0.00 | 0 |
| 2026-08-06 | West Street Life Sciences I, L.P. | Open-market buy | 500,000 | $17.00 | 3,020,632 |
| 2026-08-06 | West Street Life Sciences I, L.P. | Conversion | 478,498 | $0.00 | 2,520,632 |
| 2026-08-06 | West Street Life Sciences I, L.P. | Conversion | 1,957,134 | $0.00 | 2,042,134 |
| 2026-08-06 | WSLS OFFSHORE INVESTMENTS, SLP | Conversion (derivative) | 4,445,275 | $0.00 | 0 |
| 2026-08-06 | WSLS OFFSHORE INVESTMENTS, SLP | Conversion (derivative) | 18,181,830 | $0.00 | 0 |
| 2026-08-06 | WSLS OFFSHORE INVESTMENTS, SLP | Open-market buy | 500,000 | $17.00 | 3,020,632 |
| 2026-08-06 | WSLS OFFSHORE INVESTMENTS, SLP | Conversion | 478,498 | $0.00 | 2,520,632 |
| 2026-08-06 | WSLS OFFSHORE INVESTMENTS, SLP | Conversion | 1,957,134 | $0.00 | 2,042,134 |
| 2026-08-06 | Broad Street Principal Investments, L.L.C. | Conversion (derivative) | 4,445,275 | $0.00 | 0 |
| 2026-08-06 | Broad Street Principal Investments, L.L.C. | Conversion (derivative) | 18,181,830 | $0.00 | 0 |
| 2026-08-06 | Broad Street Principal Investments, L.L.C. | Open-market buy | 500,000 | $17.00 | 3,020,632 |
| 2026-08-06 | Broad Street Principal Investments, L.L.C. | Conversion | 478,498 | $0.00 | 2,520,632 |
| 2026-08-06 | Broad Street Principal Investments, L.L.C. | Conversion | 1,957,134 | $0.00 | 2,042,134 |
| 2026-08-06 | GOLDMAN SACHS ASSET MANAGEMENT, L.P. | Conversion (derivative) | 4,445,275 | $0.00 | 0 |
| 2026-08-06 | GOLDMAN SACHS ASSET MANAGEMENT, L.P. | Conversion (derivative) | 18,181,830 | $0.00 | 0 |
| 2026-08-06 | GOLDMAN SACHS ASSET MANAGEMENT, L.P. | Open-market buy | 500,000 | $17.00 | 3,020,632 |
| 2026-08-06 | GOLDMAN SACHS ASSET MANAGEMENT, L.P. | Conversion | 478,498 | $0.00 | 2,520,632 |
| 2026-08-06 | GOLDMAN SACHS ASSET MANAGEMENT, L.P. | Conversion | 1,957,134 | $0.00 | 2,042,134 |
| 2026-08-06 | GOLDMAN SACHS & CO. LLC | Conversion (derivative) | 4,445,275 | $0.00 | 0 |
| 2026-08-06 | GOLDMAN SACHS & CO. LLC | Conversion (derivative) | 18,181,830 | $0.00 | 0 |
| 2026-08-06 | GOLDMAN SACHS & CO. LLC | Open-market buy | 500,000 | $17.00 | 3,020,632 |
| 2026-08-06 | GOLDMAN SACHS & CO. LLC | Conversion | 478,498 | $0.00 | 2,520,632 |
| 2026-08-06 | GOLDMAN SACHS & CO. LLC | Conversion | 1,957,134 | $0.00 | 2,042,134 |
| 2026-08-06 | GOLDMAN SACHS GROUP INC | Conversion (derivative) | 4,445,275 | $0.00 | 0 |
| 2026-08-06 | GOLDMAN SACHS GROUP INC | Conversion (derivative) | 18,181,830 | $0.00 | 0 |
| 2026-08-06 | GOLDMAN SACHS GROUP INC | Open-market buy | 500,000 | $17.00 | 3,020,632 |
| 2026-08-06 | GOLDMAN SACHS GROUP INC | Conversion | 478,498 | $0.00 | 2,520,632 |
| 2026-08-06 | GOLDMAN SACHS GROUP INC | Conversion | 1,957,134 | $0.00 | 2,042,134 |
Source: SEC EDGAR Form 4 filings. For informational purposes only — not investment advice.