Top Funding Rounds Week of September 28th
From OpenAI's $30B round to Mistral AI's Series D, this past week saw heavy investment in AI and energy. Discover the top 20 venture deals in our analysis.
Published October 5, 2026 by Jacob Klionsky
- 01$30BEquity
OpenAI, the AI lab behind ChatGPT, finalized a $30B investment at an $852B valuation from SoftBank, with Amazon and Nvidia among the main contributors.
- 02$3.4BSeries D
Mistral AI, a Paris-based AI startup, raised €3 billion in a Series D at a reported post-money valuation of over €21 billion led by Samsung Electronics with participation from Scaleup Europe Fund (managed by EQT) and existing investor PSG Equity.
- 03$1.1BEquity
Eni Plenitude, an energy transition company, completed a €1.56bn capital raise that values the company at a €10.75bn equity valuation (€13.1bn enterprise value) with Ares contributing over €1bn alongside majority shareholder Eni and Energy Infrastructure Partners.
- 04$1BSeries C
Instinct, a viral AI agent startup, raised $1 billion in a Series C at a $10 billion valuation from investors including Sequoia Capital, Benchmark Capital and Coatue.
- 05$907.4MEquity
Synthos Green Energy, a small modular reactor (SMR) construction company, raised about EUR 800 million in its first private funding round from a mix of Polish entrepreneurs and foreign investors including GE Vernova.
- 06$800MEquity
Maxwell Power, a residential and small commercial solar and battery storage company, received an $800 million investment commitment from Fairtide Partners to purchase battery storage and solar projects.
- 07$636.3MFunding Round
Rezolv Energy, an Actis-backed renewable developer, secured an up to €561 million project financing package for the 1.3GWp Dama Solar project, a green loan backed by an anchor EIB investment (with an InvestEU guarantee) and provided by a consortium of 14 lenders including EIB, EBRD, IFC, BSTDB and ten commercial banks (Erste Group, UniCredit, Banca Comercială Intesa Sanpaolo Romania, Société Générale, OTP Bank, ČSOB, Raiffeisen Bank S.A., Raiffeisenlandesbank Niederösterreich-Wien, Piraeus Bank and Siemens Bank)
- 08$555MSeries G
Devoted Health, a Medicare Advantage insurer, raised $555 million in a Series G and secured a $622 million tender-offer commitment from the same investors.
- 09$430MEquity
TXSE Group, parent of the Texas Stock Exchange, raised $430 million in a third-round financing from existing owners including BlackRock, Charles Schwab, Citadel Securities, J.P. Morgan, Goldman Sachs and Bank of America
- 10$350MEquity
EliseAI, a housing and healthcare-focused AI company, raised $350 million in a funding round at a $4 billion valuation led by Andreessen Horowitz and Bessemer Venture Partners with participation from Ontario Teachers' Pension Plan, Sapphire Ventures and Navitas Capital
- 11$268MEquity
SMT Energy, a battery energy storage developer and operator, secured up to $268 million in an equity partnership with Climate Adaptive Infrastructure.
- 12$255.5MSeries B
Armadin, an AI-era security startup, raised $255.5 million in a Series B at a $2.5B valuation led by Andreessen Horowitz and Accel, with Bain Capital Ventures, Redpoint, 8VC, Ballistic Ventures, Google Ventures, In-Q-Tel, Kleiner Perkins, and Menlo Ventures
- 13$251MSeries D
Varda, a microgravity-enabled life sciences company, raised $251 million in a Series D led by Lux Capital and Natural Capital with participation from Founders Fund, Khosla Ventures, Caffeinated Capital, General Catalyst, 8090 Industries, Giant Step, and Also Capital.
- 14$223MSeries B
GMI Cloud, a Taiwan-based on-demand GPU infrastructure startup, raised $663M in total capital composed of a $223M Series B led by ARCHIV with participation from Nvidia, Redwood, DSC Investment, KT Corp., Kyobo Life, KB Investment and Trend Micro, plus a $440M credit facility from ChinaTrust Commercial Bank
- 15$220MEquity
World model startup General Intuition raised $220 million at a $6.2 billion valuation from Valor Equity Partners, Atreides, Seven Seven Six, Point72, Khosla Ventures and General Catalyst
- 16$200MSeries C
PaleBlueDot AI, a Super Intelligence infrastructure platform, raised $200 million in a Series C at a $3.2 billion valuation led by ComputeCore with participation from B Capital and other global investors.
- 17$200MEquity
Shield AI, an AI pilot systems company, raised $200 million in a financing round.
- 18$185MEquity
NorthStar Medical Radioisotopes, a commercial-stage radiopharmaceutical company producing radioisotopes including no-carrier-added Actinium-225, secured a multi-year growth-capital facility of up to $185 million (with $100 million upfront) led by Hercules Capital.
- 19$182.2MSeries C
Simple Energy, an Indian electric two-wheeler maker, raised $180 million in an all-equity Series C round led by the Dr Arokiaswamy Velumani Family Office with participation from founder and CEO Suhas Rajkumar, co-founder and CFO Ankit Gupta, HNI Amit Mishra and the Haran Family Office
- 20$175.3MSeries B
Reverion, an EnergyTech company building reversible solid oxide fuel cell power plants, raised €154.2 million in a Series B led by Kembara with participation from Allianz, KfW Capital, Aurum Impact, Carbon Equity, Extantia, Energy Impact Partners, UVC Partners, the European Innovation Council Fund (EIC Fund), alfa8, and Possible Ventures
