Current Snapshot
Latest Year
2025
2025 Participants
3
2025 Assets
$27,898
2025 Contributions
$0
Historical Graphs
Total Assets Over Time
Aggregate end-of-year assets by filing year, excluding zero-asset years
Participants Over Time
Largest reported end-of-year plan headcount by filing year, used to avoid double-counting participants across overlapping plans
Company Timeline
Year summaries and individual filings are combined here so you can stay in one place while moving across years and plan filings.
| Year / Filing | Filings | Participants | Assets | Contributions | Contrib./Participant |
|---|---|---|---|---|---|
| 2025 | 1 | 3 | $0 | $0 | - |
| Spero Inc 401(K) Plan | - | 3 | - | - | - |
| 2024 | 1 | 3 | $0 | $0 | - |
| Spero Inc 401(K) Plan | - | 3 | - | - | - |
| 2023 | 1 | 3 | $27,898 | $0 | - |
| Spero Inc 401(K) Plan | - | 3 | $27,898 | - | - |
| 2022 | 1 | 4 | $33,464 | $0 | - |
| Spero Inc 401(K) Plan | - | 4 | $33,464 | - | - |
| 2021 | 1 | 2 | $133,094 | $0 | - |
| Spero Inc 401(K) Plan | - | 2 | $133,094 | - | - |
| 2020 | 1 | 1 | $218,220 | $0 | - |
| Spero Inc 401(K) Plan | - | 1 | $218,220 | - | - |
| 2019 | 1 | 2 | $162,812 | $0 | - |
| Spero Inc 401(K) Plan | - | 2 | $162,812 | - | - |
| 2018 | 1 | 1 | $0 | $0 | - |
| Spero Inc 401(K) Plan | - | 1 | - | - | - |