Manufacturer of linear power generators designed to bring affordable, reliable and net-zero carbon grid of the future.
Manufacturer of linear power generators designed to bring affordable, reliable and net-zero carbon grid of the future.
Energy Production📍 Menlo Park, CAFounded 2010
Current Valuation
$850.11M
as of 2022-Q2
PRIVATE
QL Price
$438.08M
-48% vs last round
QuantLogix's current estimate for Mainspring, published 2026-09-27 — below the last disclosed round of $850.11M (2022-Q2).
Confidence
medium
Basis
secondary led
What backs this price
Last disclosed round
$850.11M
2022-Q2
weight 0.05
Secondary market print
$400.4M
2026-06-27
weight 0.58
How this price has held up
No round has priced for Mainspring since QuantLogix began publishing a price for it, so there is nothing to grade yet. The claim above is on the record from 2026-09-27 and will be graded against the next priced round. See the full accuracy record →
Which publicly-traded funds already hold it, what $10,000 buys, and whether any route is open to you.
Cite this price as QuantLogix QL Price, Mainspring, 2026-09-27 (51f41d3ae7ddfef2).
The id pins this exact claim, so a citation stays checkable after the price moves.
Model estimate for research — not a quote, target price, or investment advice.
IPO Outlookprivate
Is Mainspring going public?
No. Mainspring is private and has not filed to go public. There is no S-1 on file.
What is Mainspring's valuation in 2026?
Mainspring is valued at $850.11M as of 2022-Q2, set by its Series E ($150M, May 2022). That is the last confirmed mark, not a live price — private shares do not trade continuously.
Has Mainspring filed an S-1?
No public S-1 is on file for Mainspring.
How much has Mainspring raised?
Mainspring has raised $406.2M in total, most recently a Series E of $150M in May 2022.
Is Mainspring publicly traded — can you buy Mainspring stock?
No. Mainspring is a private company — its shares are not listed on any exchange and there is no ticker. The routes to exposure are pre-IPO secondary marketplaces and funds (accredited investors), employee tender offers when the company runs one, and public companies with read-through exposure. QuantLogix maps every route it can verify for Mainspring on its Pre-IPO Access Desk.
Answers are derived from the roster record shown on this page — filing status, last round and confirmed marks. Where the record is silent, the answer says so rather than guessing.
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 4mo 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
Secondary price return by period
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
Round
Amount
Date
Lead Investor
Post-Money
Series E
$150M
May 2022
—
$850.11M
Talent Signal
Hiring trend
▶ Hiring steady
+7% vs 2026-08
Open roles
87
via lever
Product-build share
67%
engineering, research, product, design
Trajectory
steady
heavy product build — 67% of open roles are product-building functions (engineering/research/product) — 33 of 87 open roles are hardware.
Actively hiring with no tracked executive churn.
Open roles by month
Open roles by function
■ product-building ■ go-to-market / G&A
Associate Embedded System Lab ManagerDirector of Mechanical EngineeringDirector, Electrical Strategic SourcingDirector, Reliability EngineeringElectrical Engineer - Inverter & Grid IntegrationElectrical Engineer - Power Electronics
Counted from Mainspring's live job board as of 2026-09-16; role functions classified from posting titles. Open-role counts are an activity signal, not headcount. Refreshed monthly.
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.