Back to list

Mainspring

Manufacturer of linear power generators designed to bring affordable, reliable and net-zero carbon grid of the future.
Energy Production 📍 Menlo Park, CA Founded 2010
Current Valuation
$850.11M
as of 2022-Q2
PRIVATE
Manufacturer of linear power generators designed to bring affordable, reliable and net-zero carbon grid of the future.

Company Profile

Founded
2010
HQ
Menlo Park, CA
Employees
478
Total Raised
$406.2M
Last Round
Series E — $150M (May 2022)
IPO Status
private

Fundraising Status

Series E · $150M · 4y 3mo ago
privateTotal raised $406.2M

Secondary Market

Implied price / share
$3.8
Last round price / share
$8.07
vs last round
-52.9%
Open interest
6
Last round price vs secondary price
Last round vs current secondary price per share$8.07Last round$3.80Current
Secondary price return by period
Secondary market period returns3-month-10.2%6-month-5.2%1-year-49.9%All-time-52.5%
Implied per-share price from private secondary transactions, as of Jun 2026. This is a point estimate, not a quote — the feed carries no bid, ask or spread, and a secondary print is evidence of what someone paid on that date rather than a live market. Compare across every tracked name →

Latest Funding Round

RoundAmountDateLead InvestorPost-Money
Series E$150MMay 2022$850.11M
EnergyClean EnergyOil and Gas
Private-company numbers are not real-time. Reflects publicly disclosed valuations from press releases, news reports, and tender offers as of 2022-Q2. Refreshed quarterly.