Fourth Power
PrivateLast Round
Series A
Extension
Sep 16, 2025
Total Funding Raised
$44.11M
Company Overview
Fourth Power operates in Energy & Sustainability and is based in Cambridge, Massachusetts. Its latest recorded funding round was a Series A Extension round in September 2025.
Fourth Power is a clean energy company that develops utility-scale thermal battery storage solutions to capture excess wind and solar energy for on-demand grid dispatch.
Sector
Energy & Sustainability
Verticals
Energy Storage, Renewable Energy, Smart Grid
Business Model
B2B
Customer Profile
Hardware Sales
AI Layer
Non-AI
Historical Pricing
Historical view of private secondary pricing and transaction trends.
Fourth Power Comparables
Compare Fourth Power with similar companies based on industry and business-model similarity.
| Company | Similarity | Market Cap |
|---|---|---|
| Malta Inc | 81% | |
| Ambri | 78% | |
| MGA Thermal | 77% |
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Fourth Power Funding Rounds
Historical fundraising activity
| Round | Date | Amount Raised | Valuation | Investors | Sources |
|---|---|---|---|---|---|
| Series A Extension | Sep 16, 2025 | ||||
| Series A | Dec 12, 2023 | ||||
| Grant | Feb 27, 2023 | ||||
| Grant | Dec 18, 2018 | ||||
| Grant | Nov 28, 2012 |
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Key People
Founding team and executive leadership
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Fourth Power Investors
Notable investors and investment history
| Investor | Rounds |
|---|---|
| Munich Re Ventures | Series A Extension |
| Breakthrough Energy Ventures | Series A, Series A Extension |
| BVCC | Series A |
| Department of Energy | Grant |
| DCVC (Data Collective) | Series A Extension, Series A |
Market signals
Structured signals derived from secondary market and firmographic data.
- Feb 27, 2023
$10K grant received from the Department of Energy.
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Recent news
Latest coverage and updates
- expands_facilitiesSep 14, 2026
On Sep 14th '26, Fourth Power, Inc. opens a new facility in Massachusetts and begins commissioning its first full-scale demonstration of its energy storage technology.
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Fourth Power Filings
Explore SEC and related filing metadata, where available.
| Type | Date | Amount Offered | Amount Sold | Filing | Pages | Download |
|---|
Filing documents are not displayed on this public page. Request access to learn about available coverage.
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Frequently Asked Questions
Common questions about Fourth Power's valuation, stock price, and market status.
Is Fourth Power a public or private company?
Fourth Power is a private company.
What is the current stock price of Fourth Power?
Fourth Power is a private company, so its shares have no public market price. Caplight tracks Fourth Power's secondary market activity and provides MarketPrice™ estimates of its share price to Caplight users.
How much is Fourth Power worth (valuation)?
Valuation information for Fourth Power is not publicly available.
Can I buy Fourth Power stock?
Fourth Power shares may be available on secondary markets subject to transfer restrictions. Caplight facilitates secondary market transactions for accredited investors.
When was Fourth Power's last funding round?
Fourth Power's most recent funding round was Series A Extension on September 16, 2025.
Who are the main investors in Fourth Power?
Key investors in Fourth Power include Munich Re Ventures, Department of Energy, DCVC (Data Collective).
Will Fourth Power IPO soon?
No public IPO plans have been announced for Fourth Power.
How can I track Fourth Power secondary market activity?
Caplight tracks bids, offers, and trades in Fourth Power's shares on secondary markets.