Funded Startups in Waltham
Disclosed round sizes in Waltham span from as low as $4M (Monaire, 2024-03-20) to a single extreme: Thermo Fisher Scientific’s post-IPO debt round at $741M…
Disclosed round sizes in Waltham span from as low as $4M (Monaire, 2024-03-20) to a single extreme: Thermo Fisher Scientific’s post-IPO debt round at $741M on 2022-10-14, which dwarfs the next-largest disclosed amounts in the table (e.g., Kailera Therapeutics $600M on 2025-10-19; NanoMosaic $3M on 2025-11-28 is among the smallest). That same breadth shows up in the stage labels: five of the 50 rows carry an “undisclosed” amount and many more use “Series Unknown,” with Series appearing specifically as Series B, Series C, Series D, Seed, and Post-IPO Debt across different clusters.
Most activity concentrates in a recent window: the latest 10 entries run from 2025-11-28 (NanoMosaic) back to 2024-12-23 (TScan Therapeutics). Sector-wise, Biotechnology dominates the list with more than three entries (e.g., NanoMosaic, Invivyd, Triveni Bio, Zenas BioPharma, Morphic Therapeutic, and many others), while Hardware and Energy also recur multiple times (e.g., Vicarious Surgical and Veo Robotics for Hardware; Adden Energy and Tecogen for Energy).
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Frequently asked
Which round size is the standout outlier, and how does it compare to the rest of the disclosed amounts?
Thermo Fisher Scientific’s post-IPO debt round at $741M (2022-10-14) is the only disclosed amount above $600M; the next-largest disclosed amount is Kailera Therapeutics at $600M (2025-10-19). After that, the table shifts into a much lower range, with several rounds in the tens of millions (e.g., Dianthus Therapeutics $100M on 2022-04-19; Deciphera Pharmaceuticals $125M on 2023-01-19).
Are “undisclosed” or “Series Unknown” entries frequent enough to affect analysis of stage and size?
Yes: five of the 50 rows list an “undisclosed” amount (e.g., Constant Contact on 2025-10-09; TScan Therapeutics on 2024-12-23; InfoBionic on 2023-10-16; OpenClinica on 2023-02-21; TRINITY on 2022-08-08). Separately, many more rounds are labeled “Series Unknown,” including CallMiner ($8M on 2025-06-16) and Qeepsake ($450K on 2024-11-20), which limits stage-based comparisons for those rows.
Do entries cluster in a particular recency window based on the round dates shown?
The most recent entries cluster tightly: the latest date in the table is 2025-11-28 (NanoMosaic), and the top of the list runs down through 2025-10 and 2025-08 (e.g., Kailera Therapeutics $600M on 2025-10-19; Invivyd $58M on 2025-08-20). The oldest date shown is 2022-02-09 (Ventus Therapeutics), so the displayed set spans roughly 3 years and concentrates meaningfully in 2024–2025.
Is one sector clearly over-represented compared to others in this Waltham list?
Biotechnology is the dominant repeat category, appearing in far more than three entries (e.g., NanoMosaic, Invivyd, Triveni Bio, Spectrawave, Zenas BioPharma, and Morphic Therapeutic). Other sectors recur but with less density, such as Hardware (e.g., Vicarious Surgical $45M on 2023-08-02; Veo Robotics $14M on 2023-04-25) and Energy (e.g., Adden Energy $15M on 2024-09-03; Tecogen $2M on 2023-10-09).
Which entries are worth attention because the disclosed amount is at the extremes (very small vs. very large)?
At the small end, the lowest disclosed amount is $4M for Monaire on 2024-03-20 (with other small rounds like Tubender at $10K on 2025-03-18). At the large end, beyond the $741M outlier (Thermo Fisher Scientific, 2022-10-14), the next-largest disclosed amounts include Kailera Therapeutics at $600M (2025-10-19) and several mid-to-high eight-figure rounds such as BostonGene $150M (2022-04-06) and Ventus Therapeutics $140M (2022-02-09).
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