Series B investors in Boston
This slice of our investor database holds 51 Series B Boston investors. They sit in 4 cities across 1 country, most of them in Boston (36), Cambridge (12) and Waltham (2). The sectors they back most often here are SaaS (35), Health tech (27) and Fintech (22). The median firm in this slice has made 67 investments; across the slice the total is 6,763. The median number of exits is 16. By stage: Pre-seed (29), Seed (47), Series A (49), Series B (51) and Growth (40). The largest portfolios in this slice belong to Battery Ventures, Polaris Partners and Atlas Venture. Every row below is shown in full except the contact details, which are the paid part of the dataset. The numbers on this page are recomputed from the database, so they change when the data does.
- 51 firms in this slice.
- Most concentrated in Boston (36).
- Median investments per firm: 67.
- Leading sector: SaaS (35).
- 51 rows carry a contact address; those are the paid part.
| By stage | Investors |
|---|---|
| Pre-seed | 29 |
| Seed | 47 |
| Series A | 49 |
| Series B | 51 |
| Growth | 40 |
| By sector | Investors |
|---|---|
| saas | 35 |
| healthtech | 27 |
| fintech | 22 |
| mobile | 20 |
| biotech | 19 |
| consumer | 19 |
| ai | 17 |
| data-analytics | 16 |
| enterprise | 16 |
| ecommerce | 13 |
| By city | Investors |
|---|---|
| Boston | 36 |
| Cambridge | 12 |
| Waltham | 2 |
| Newton | 1 |
| By type | Investors |
|---|---|
| Venture funds | 49 |
| Corporate VC | 1 |
| Family offices | 1 |
Number of investments made, by firm.
| Portfolio size | Investors |
|---|---|
| 0–10 | 3 |
| 10–25 | 6 |
| 25–50 | 11 |
| 50–100 | 12 |
| 100+ | 19 |
Preview — 15 of 51
| Investor | Type | Location | Stages | Investments | Contact |
|---|---|---|---|---|---|
| Battery Ventures | Venture funds | Boston, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| Polaris Partners | Venture funds | Boston, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| Atlas Venture | Venture funds | Cambridge, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| Spark Capital | Venture funds | Boston, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| Summit Partners | Venture funds | Boston, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| F-Prime Capital | Venture funds | Cambridge, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| SV Health Investors | Venture funds | Boston, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| RA Capital | Venture funds | Boston, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| Flagship Pioneering | Venture funds | Cambridge, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| Wellington Management | Venture funds | Boston, US | Series B, Seed, Growth, Series A | — | |
| Boston Millennia Partners | Venture funds | Boston, US | Series B, Seed, Growth, Series A | — | |
| HLM Venture Partners | Venture funds | Boston, US | Series B, Growth, Series A | — | |
| Bain Capital | Venture funds | Boston, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| Third Rock Ventures | Venture funds | Boston, US | Series B, Seed, Growth, Pre-seed, Series A | — | |
| Omega Funds | Venture funds | Boston, US | Series B, Seed, Growth, Pre-seed, Series A | — |
Questions
What is free here?
Name, type, stages, sectors, city and country, website, investment and exit counts — as aggregates across all 51 rows and row by row for the first fifteen. Contact addresses are not part of the free view and are physically absent from this page.
What does buying add?
The full export of all 51 rows in XLSX and CSV, including contact email (51 rows have one). Access follows the list, not a file: the export is rebuilt and you always download the current version.
Where does the data come from?
Source and method are described on the investor data sources page. We do not claim verification that did not happen — each row carries a confidence level. An investor who asks to be excluded is removed from both the preview and the export.
Where this data comes from · updated 9/5/2026