# Series A investors based in Boston (2026 list) > 56 series A investors based in Boston, 93% active in the last 12 months. Led by MassChallenge, Battery Ventures, Polaris Partners. Ranked by what they funded. Source: https://millionrounds.com/lists/series-a-investors-based-in-boston (Millionrounds; every figure on the page links to its filing or article) [Investor Lists](https://millionrounds.com/lists) # Series A investors based in Boston Updated 7 November 2026 Firms with an address in Boston that we have watched take part in a Series A round in the last two years. [See all 56 *→*](https://millionrounds.com/login?join=1&next=%2Fapp%2Finvestor-lists%2Fseries-a-investors-based-in-boston)The top 25 **56** investors on the list *-1* this week **658** cheques in 12 months *+1%* against the market **$19M** median round they joined *+138%* against the market median **93%** wrote a cheque in 12 months **68%** have led a round ## The Top 25 Ordered by cheques observed, never by anything anyone paid for Deploying now (25) - 1 [MassChallenge](https://millionrounds.com/fund/masschallenge) *Deploying now* Accelerator · United States **984** **$1.8M** median round **Sept 2026** last seen - 2 [Battery Ventures](https://millionrounds.com/fund/battery-ventures) *Deploying now* VC firm · United States **658** **$32M** median round **Nov 2026** last seen - 3 [Polaris Partners](https://millionrounds.com/fund/polaris-partners) *Deploying now* VC firm · United States **490** **$36M** median round **Oct 2026** last seen - 4 [RA Capital Management](https://millionrounds.com/fund/ra-capital-management) *Deploying now* Private equity · United States **395** **$93M** median round **Nov 2026** last seen - 5 [Summit Partners](https://millionrounds.com/fund/summit-partners) *Deploying now* Private equity · United States **356** **$81M** median round **Oct 2026** last seen - 6 [Wellington Management](https://millionrounds.com/fund/wellington-management) *Deploying now* VC firm · United States **297** **$130M** median round **Oct 2026** last seen - 7 [Cormorant Asset Management](https://millionrounds.com/fund/cormorant-asset-management) *Deploying now* Private equity · United States **176** **$102M** median round **Oct 2026** last seen - 8 [406 Ventures](https://millionrounds.com/fund/406-ventures) *Deploying now* VC firm · United States **136** **$15M** median round **Oct 2026** last seen - 9 [Omega Funds](https://millionrounds.com/fund/omega-funds) *Deploying now* VC firm · United States **104** **$88M** median round **Sept 2026** last seen - 10 [Flare Capital](https://millionrounds.com/fund/flare-capital-partners) *Deploying now* VC firm · United States **93** **$12M** median round **Oct 2026** last seen - 11 [MassMutual Ventures](https://millionrounds.com/fund/massmutual-ventures) *Deploying now* VC firm · United States **84** **$14M** median round **Oct 2026** last seen - 12 [Pillar VC](https://millionrounds.com/fund/pillar-vc) *Deploying now* VC firm · United States **83** **$8.2M** median round **Sept 2026** last seen - 13 [Castle Island Ventures](https://millionrounds.com/fund/castle-island-ventures) *Deploying now* VC firm · United States **78** **$7M** median round **Oct 2026** last seen - 14 [The E14 Fund](https://millionrounds.com/fund/e14-fund) *Deploying now* VC firm · United States **72** **$8M** median round **Oct 2026** last seen - 15 [PSG](https://millionrounds.com/fund/providence-equity-partners) *Deploying now* VC firm · United States **68** **$50M** median round **Aug 2026** last seen - 16 [Underscore VC](https://millionrounds.com/fund/underscore-vc) *Deploying now* VC firm · United States **65** **$7M** median round **Sept 2026** last seen - 17 [HubSpot Ventures](https://millionrounds.com/fund/hubspot-ventures) *Deploying now* Corporate VC · United States **64** **$25M** median round **Nov 2026** last seen - 18 [Four Cities Capital](https://millionrounds.com/fund/four-cities-capital) *Deploying now* VC firm · United States **62** **$5.3M** median round **Oct 2026** last seen - 19 [Bain Capital](https://millionrounds.com/fund/bain-capital) *Deploying now* Private equity · United States **58** **$50M** median round **Aug 2026** last seen - 20 [Spectrum Equity](https://millionrounds.com/fund/spectrum-equity) *Deploying now* Private equity · United States **55** **$62M** median round **Sept 2026** last seen - 21 [Elephant](https://millionrounds.com/fund/elephant) *Deploying now* VC firm · United States **54** **$16M** median round **Jul 2026** last seen - 22 [Longwood Fund](https://millionrounds.com/fund/longwood-fund) *Deploying now* VC firm · United States **53** **$60M** median round **Aug 2026** last seen - 23 [Optum Ventures](https://millionrounds.com/fund/optum-ventures) *Deploying now* VC firm · United States **53** **$25M** median round **Oct 2026** last seen - 24 [Glasswing Ventures](https://millionrounds.com/fund/glasswing-ventures) *Deploying now* VC firm · United States **50** **$5.2M** median round **Oct 2026** last seen - 25 [Raptor Group](https://millionrounds.com/fund/raptor-group) *Deploying now* Private equity · United States **50** **$15M** median round **Sept 2026** last seen **31 more on this list** All 56 are in the app, with filters for stage, sector and market. A free account shows 10 per search, Pro up to 1,000. [See the whole list *→*](https://millionrounds.com/login?join=1&next=%2Fapp%2Finvestor-lists%2Fseries-a-investors-based-in-boston) ## The Newest Cheques Rounds this list's investors joined most recently - **5** Nov **[Alethio Therapeutics](https://millionrounds.com/company/alethio-therapeutics)** Series A · $90M *Led by* [RA Capital Management](https://millionrounds.com/fund/ra-capital-management) - **4** Nov **[Shackleton AI](https://millionrounds.com/company/shackleton-ai)** Seed · $5M *Led by* [Battery Ventures](https://millionrounds.com/fund/battery-ventures) - **3** Nov **[Traversal](https://millionrounds.com/company/traversal)** Series B · $120M *With* [Battery Ventures](https://millionrounds.com/fund/battery-ventures) - **3** Nov **[Applied Compute](https://millionrounds.com/company/applied-compute)** Other · $350M *With* [HubSpot Ventures](https://millionrounds.com/fund/hubspot-ventures) - **2** Nov **[Ozlo](https://millionrounds.com/company/ozlo)** Series B · $22M *With* [Drive by DraftKings](https://millionrounds.com/fund/drive-by-draftkings) - **29** Oct **[Dren Bio](https://millionrounds.com/company/dren-bio)** Other · $350M *With* [Cormorant Asset Management](https://millionrounds.com/fund/cormorant-asset-management) ## Stages This Year 598 rounds - Other **17%** - Series A **17%** - Venture **14%** - Series B **12%** - Seed **12%** - Other **29%** ## What They Backed Sectors, last 12 months - AI **187** - Biotech **150** - Healthcare **75** - Pharma **56** - Big Data & Analytics **32** - Fintech **28** ## Cheques by Quarter Led Joined 176 Q1 25 147 Q2 25 157 Q3 25 216 Q4 25 213 Q1 26 171 Q2 26 164 Q3 26 38 Q4 26 The last bar is the quarter still running. ## Lists Like This - [AI investors based in San Francisco 353](https://millionrounds.com/lists/ai-investors-based-in-san-francisco) - [AI investors based in New York 345](https://millionrounds.com/lists/ai-investors-based-in-new-york) - [Seed investors based in San Francisco 273](https://millionrounds.com/lists/seed-investors-based-in-san-francisco) - [Series A investors based in San Francisco 266](https://millionrounds.com/lists/series-a-investors-based-in-san-francisco) - [Series A investors based in New York 255](https://millionrounds.com/lists/series-a-investors-based-in-new-york) - [Seed investors based in New York 227](https://millionrounds.com/lists/seed-investors-based-in-new-york) - [AI investors based in London 223](https://millionrounds.com/lists/ai-investors-based-in-london) - [Series B investors based in New York 198](https://millionrounds.com/lists/series-b-investors-based-in-new-york) - [Fintech investors based in New York 197](https://millionrounds.com/lists/fintech-investors-based-in-new-york) [All investor lists *→*](https://millionrounds.com/lists) ## Quick answers about series A investors based in Boston ### Who are the most active series A investors based in Boston? By cheques observed, the most active are MassChallenge, Battery Ventures, Polaris Partners, RA Capital Management and Summit Partners. ### How many series A investors based in Boston are there? 56 are on record. 93% made an investment in the last 12 months and 68% have led a round. ### Which stages do series A investors based in Boston back? Of the rounds with a named stage in the last 12 months, mostly Series A (25%) and Series B (18%). ### How big are the rounds series A investors based in Boston join? The typical (median) round among the leading investors here is $25M. ### Which sectors do series A investors based in Boston back most? In the last 12 months, mostly AI, Biotech and Healthcare. ### Which series A investors based in Boston lead the most rounds? Battery Ventures (29 led), RA Capital Management (15 led) and Wellington Management (15 led). ### What have series A investors based in Boston invested in recently? Recent rounds include Alethio Therapeutics (Series A, Nov 2026, with RA Capital Management), Shackleton AI (Seed, Nov 2026, with Battery Ventures) and Traversal (Series B, Nov 2026, with Battery Ventures). ### How is this list of series A investors based in Boston ranked? By cheques observed, from the rounds and filings we watched, and never by anything anyone paid for. It is rebuilt every night. Built from the rounds we watched, refreshed every night. [How we count](https://millionrounds.com/methodology) · [Report a correction](https://millionrounds.com/corrections)