About Intersouth Partners
Intersouth Partners is a venture capital firm founded in 1984. It is primarily based out of Durham, United States. As of May 2021, Intersouth Partners has invested in 89 companies. It primarily invests in Series B round in United States based startups. Its investments are spread across a wide range of sectors from Life Sciences to Enterprise Applications and High Tech. Most recently it participated in the $***** Series C round of Advanced Animal Diagnostics Overall, Intersouth Partners portfolio has seen 6 IPOs and 47 acquisitions including key companies like MaxCyte, Lyra Therapeutics and Insmed. A lot of funds co-invest with Intersouth Partners, with names like Polaris Partners sharing a substantial percentage of its portfolio. Intersouth Partners has team of 6 people including 5 partners.Key Metrics
Team Members
Portfolio Count
Portfolio Sectors
Portfolio Locations
Rounds of Entry
Series A, Series B & 4 more
Portfolio IPOs
Portfolio Soonicorns
Intersouth Partners' List of Top Investments
Intersouth Partners has a portfolio of 89 companies. Their most notable investments are in Quantum Photonics and Quantum Photonics.Their portfolio spans across United States, China and India. They have invested in Life Sciences, Enterprise Applications, High Tech and 22 other sectors, across stages such as Series A, Series B and 4 more. Here is the list of top investments by Intersouth Partners:
1. MaxCyte
Provider of instrument systems for processing and modification of cells. It offers MaxCyte STX, a single transfection system (TS) that uses flow electroporation for cell processing; MaxCyte VLX Large Scale TS, an instrument for large volume transient transfection. The company also provides transfection insourcing services, including the generation of cells transfected with the target of interest, recombinant protein production, and others.
Key facts about MaxCyte
- Founded Year: 1998
- Location: Gaithersburg (United States)
- Annual Revenue: $38.6M as on Dec 31, 2024
- Stage: Public
- Total Funding till date: $20.7M
- Employee Count: 71 as on Dec 31, 2022
- Investors: Vitruvian Partners, Casdin Capital and 7 Others
- Latest Funding Round: Post IPO, May 01, 2020, $*****
- Highlight: Public
Biotechnology firm innovating localized therapies for chronic rhinosinusitis (CRS). The company focuses on developing innovative therapies for the localized treatment of CRS, an inflammatory disease affecting millions. They leverage expertise in materials science, drug development, and formulation to create proprietary technology. This technology delivers medicines directly and consistently to affected tissues for sustained periods with a single administration. Their product candidates are bioabsorbable nasal implants designed for in-office administration, delivering continuous drug therapy to the sinonasal passages. The aim is to provide long-acting medication directly to sinonasal tissues inaccessible with conventional approaches, breaking the cycle of medical management for this underserved population. This approach integrates anti-inflammatory medication and advanced materials engineering to create a treatment solution.
Key facts about Lyra Therapeutics
- Founded Year: 2005
- Location: Watertown (United States)
- Annual Revenue: $1.56M as on Dec 31, 2023
- Stage: Public
- Total Funding till date: $110M
- Employee Count: 34 as on Mar 31, 2026
- Investors: HTIF, RA Capital Management and 9 Others
- Latest Funding Round: Post IPO, Jun 09, 2023, $*****
- Highlight: Public
3. Insmed
Developer of small molecule inhibitors for rare lung diseases. Its lead candidate is Arikayce (liposomal amikacin for inhalation), a ribosomal 30S subunit inhibitor for nontuberculous mycobacteria (NTM) lung disease. It also has an earlier-stage clinical pipeline which includes INS1009, a nebulized prodrug formulation of treprostinil that claims to have potential in rare pulmonary disorders such as pulmonary arterial hypertension (PAH), idiopathic pulmonary fibrosis (IPF) sarcoidosis, and severe refractory asthma.
Key facts about Insmed
- Founded Year: 1999
- Location: Bridgewater (United States)
- Annual Revenue: $364M as on Dec 31, 2024
- Stage: Public
- Employee Count: 1,578 as on Jan 02, 2026
- Investors: Quaker Partners Management, Foresite Capital and 12 Others
- Latest Funding Round: Grant (prize money), Apr 29, 2025, $*****
- Highlight: Public
4. Sun Pharma
Specialty generic pharmaceutical company manufactures and sells pharmaceutical formulations and APIs. Its product range covers various therapeutic segments such as psychiatry, neurology, cardiology, Diabetology, Gastroenterology, Gynaecology, Nephrology, Urology, and oncology. Its molecules covers multiple dosage forms, including tablets, capsules, injectables, inhalers, ointments, creams, and liquids. In 2022, the company recorded annual revenues of $5.39B and a net profit of $0.54B.
Key facts about Sun Pharma
- Founded Year: 1983
- Location: Mumbai (India)
- Stage: Public
- Employee Count: 20,681 as on Jan 31, 2025
- Investors: Innoeversity, Intersouth Partners and 1 Other
- Highlight: Public
Arsenal Medical is developing polymer-based foams and fibers. The company is developing a system that injects an in-situ curing elastomeric polymer material that fills and seals the aneurysm sac around a stent-graft.
Key facts about Arsenal Medical
- Founded Year: 2005
- Location: Waltham (United States)
- Stage: Series D
- Total Funding till date: $69.9M
- Employee Count: 29 as on Feb 28, 2026
- Investors: Springboard Enterprises, North Bridge Venture Partners and 4 Others
- Latest Funding Round: Grant (prize money), May 15, 2021, $*****
- Highlight: Editors' Pick
Intersouth Partners' Year-on-Year Investment Trends
Intersouth Partners has invested in 89 companies over the last 29 years, with an average of 0 new investment annually in the last 10 years. Its most recent first time investment was in Lyra Therapeutics and most recent follow-on round was in Advanced Animal Diagnostics.Intersouth Partners' Investments by Stage
Intersouth Partners has made 33 investments in Series A stage with an average round size of $10M, 21 investments in Series B stage with an average round size of $17.3M and 5 investments in Seed stage with an average round size of $1.49M.Stage of entry | No. of Investments |
|---|---|
Series A | 33 |
Series B | 21 |
Seed | 5 |
Series C | 3 |
Series D | 3 |
Others | 3 |
Note: We have considered here, only first round of investments
Intersouth Partners' Investments by Sector
Intersouth Partners has a diverse portfolio, with companies operating in the Life Sciences, Enterprise Applications, High Tech, Sustainability Tech and Semiconductors. Notably, it has invested in 60 Enterprise (B2B) companies, 59 Tech companies, 31 Software companies and at least 13 companies focusing on Saas.Sector | No. of Investments |
|---|---|
Life Sciences | 26 |
Enterprise Applications | 16 |
High Tech | 13 |
Sustainability Tech | 9 |
Semiconductors | 7 |
Others | 48 |
Note: We have considered here, only first round of investments
Intersouth Partners' Investments by Geography
Intersouth Partners has made most investments in United States (68).Intersouth Partners' recent investments
Intersouth Partners has not made any investment in 2026 so far.Here are the most recent investments by Intersouth Partners:
Filter this listDate | Company | Location | Round Details | Round Amount | Co-Investors |
|---|---|---|---|---|---|
May 11, 2021 | United States | Series C | 8438 | ||
Jan 27, 2020 | United States | Series C | 4547 | [+6] | |
Oct 08, 2018 | United States | Series D | 6718 | [+1] | |
Aug 16, 2017 | United States | Post IPO | 7031 | [+7] | |
Jul 15, 2016 | United States | Series B | 6105 |
IPOs and Publicly Listed companies in Intersouth Partners' Portfolio
6 of Intersouth Partners' portfolio companies have become public. Lyra Therapeutics got listed on the National Association of Securities Dealers Automated Quotations (NASDAQ), in May 2020 at marketcap of $198M and MaxCyte got listed on the London Stock Exchange (LSE) at marketcap of £33.2M.Here are Intersouth Partners' portfolio companies that went public:
Company | IPO Date | First Invested on | First Round of Investment | Round Size |
|---|---|---|---|---|
May 01, 2020 | Jan 27, 2020 | Series C | 3096 | |
Mar 29, 2016 | Mar 24, 2004 | Series B | 9410 | |
Oct 22, 2014 | Sep 06, 2007 | Series A | 6012 | |
Aug 05, 2005 | - | - | 1949 | |
Jun 01, 2000 | - | - | 4784 |
Acquired companies in Intersouth Partners' Portfolio
47 companies from Intersouth Partners' portfolio have been acquired. The most recent acquisition was Zenoss in May 2025 by Virtana for $*****.Here are Intersouth Partners' portfolio companies that got acquired most recently:
Company | Acquisition Date | First Invested on | First Round of Investment | Round Size |
|---|---|---|---|---|
May 14, 2025 | Aug 11, 2006 | Series A | 6968 | |
Nov 15, 2024 | - | - | 1706 | |
Aug 22, 2024 | Oct 07, 2009 | Series B | 3766 | |
Jul 17, 2024 | Nov 30, 2005 | Series B | 5853 | |
Jun 07, 2023 | Aug 28, 2003 | Series A | 1206 |
Team profile of Intersouth Partners
Intersouth Partners has a team of 6 members including 5 Partners located in United States. Intersouth Partners' team sits on the board of 4 companies.Here is a list of all team members in Intersouth Partners:
Name | Designation | Location | Board Memberships | Contact Details |
|---|---|---|---|---|
Partner | Durham | |||
Partner | Durham | |||
Partner | Durham | - | - | |
Partner | - | - | - | |
Partner | - | - | - |
Co-investors of Intersouth Partners
Over the past 29 years, 282 investors have co-invested in Intersouth Partners's portfolio companies. This includes funds and angels.
- Invested before Intersouth Partners: HHS, Alliance Technology Ventures and 29 others have invested in rounds before Intersouth Partners. There are 3 companies where HHS has invested before Intersouth Partners and 2 companies where Alliance Technology Ventures has invested before Intersouth Partners.
- Top Co-investors of Intersouth Partners: 114 investors entered a company along with Intersouth Partners. These include investors like Polaris Partners (6 companies).
- Invested after Intersouth Partners: A total of 137 investors have invested in Intersouth Partners's portfolio after their investments. Top Investors include Harbert Management (4 companies), HHS (3 companies) and Grotech Ventures (3 companies).
Recent News related to Intersouth Partners
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CSA Medical: $53 Million (Series D) Raised For Advancing RejuvenAir SystemPulse 2.0•Sep 09, 2024•TVM Capital, RejuvenAir, Yonjin Capital, SV Health Investors and 4 others
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Lyra Therapeutics Completes $30 Million Series C FinancingBusiness Wire•Jan 29, 2020•Lyra Therapeutics, Perceptive Advisors, Clifton Capital, RA Capital Management and 5 others
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CSA Medical Secures $23 Million to Advance its Cryospray™ Therapies for Esophageal Disease and COPDPR Newswire•Oct 08, 2018•RejuvenAir, Horizon, SV Health Investors, Ascension Ventures and 2 others
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Innocrin Pharmaceuticals, Inc. Raises $28 Million in Series D Financing | Business WireBusiness Wire•Apr 14, 2015•Innocrin, Eshelman Ventures, Novartis Venture Fund, Lilly Ventures and 2 others
