Eight Sleep
Sleep fitness company building temperature-regulating and sleep-tracking technology.
Who is building this.
Massimo Andreasi BassiCo-founder & CTOI build Eight Sleep’s technology as co-founder and CTO, turning thermoregulation, sensors, and data into sleep products for recovery and health. Eight Sleep is a YC Summer 2015 company founded in 2014 and recognized by TIME and Fast Company. Before Eight Sleep, I founded Staq.io, which PlayHaven acquired in 2013.
Alexandra ZatarainCo-founder & VP Brand & MarketingI build Eight Sleep’s brand and marketing around sleep fitness, using temperature-regulating and biometric technology to make sleep measurable and adjustable. I co-founded the company in 2014, helped take it through Y Combinator and a $1.8M preorder campaign, and was named to Forbes 30 Under 30 in Consumer Technology.
Cumulative raised across 7 rounds, totaling $301M.
Fundraising history.
Seed — $6M
Mar 2016Eight announced a $6M seed round after early crowdfunding and pre-orders.
Investors: Y Combinator, Yunqi Partners, Azure Capital, Cota Capital +5
Source ↗Series A — $5M
Jan 2017Eight announced an additional $5M round, bringing total funding to $11M.
Investors: Yunqi Partners, Azure Capital, Y Combinator, Stanford StartX Fund +2
Source ↗Series B — $14M
Mar 2018Eight Sleep announced a $14M Series B led by Khosla Ventures.
Led by Khosla Ventures · with Y Combinator, Yunqi Partners
Source ↗Series C — $86M
Aug 2021$500M post-money
Eight Sleep raised an $86M Series C led by Valor Equity Partners; TechCrunch later reported the round valued the company near $500M post-money.
Led by Valor Equity Partners · with SoftBank, Khosla Ventures, Founders Fund, General Catalyst +7
Source ↗Series D — $100M
Aug 2025Eight Sleep raised $100M in Series D funding to expand AI sleep technology and medical applications.
Investors: HSG, Valor Equity Partners, Atreides, Founders Fund +3
Source ↗Strategic — $50M
Mar 2026$1.5B
Eight Sleep raised a $50M strategic round led by Tether Investments at a reported $1.5B valuation.
Led by Tether Investments
Source ↗Growth — $40M
Nov 2019Eight Sleep closed $40M in new funding led by Founders Fund.
Led by Founders Fund · with Khosla Ventures, Y Combinator, Craft Ventures, 8VC +3
Source ↗
Invested in Eight Sleep.
Babak NiviInvested in Eight SleepBabak Nivi is a startup founder and angel investor best known as a co-founder of AngelList and Venture Hacks. He has also been described publicly as an early investor in Uber and an advisor to Dropbox.Y CombinatorInvestorSeed, Series A, Series B +2 rounds
- Yunqi PartnersInvestorSeed, Series A, Series B participant
Sleep fitness company building temperature-regulating and sleep-tracking technology.
Sleep fitness company building temperature-regulating and sleep-tracking technology.
Press
Supports product positioning, Pod features, clinical-result claims, and sleep system description.
linkedin.comEight Sleep LinkedIn company profileSupports company location, founded year, company size range, customer scale, geographic availability, and investor overview.
ycombinator.comEight Sleep company profileSupports YC S15 status, New York location, team size, founding year, and founder roles for Matteo Franceschetti, Massimo Andreasi Bassi, and Alexandra Zatarain.
prnewswire.comEight Announces $6 Million Seed Round To Change The Future Of SleepSupports 2016 $6M seed round, early investors, pre-order traction, founding year, and New York base.
prnewswire.comEight Closes Series A FundingSupports 2017 $5M Series A/additional funding, investors, total funding at the time, and early customer/geographic traction.
eightsleep.comOur (continued) commitment to healthier livesSupports 2018 $14M Series B led by Khosla Ventures and 2.5M nights tracked / 20,000-customer milestone at the time.
eightsleep.comNew Funding to Scale The Sleep Fitness MovementSupports 2021 $86M Series C led by Valor Equity Partners with SoftBank, Khosla Ventures, Founders Fund, and General Catalyst participation.
techcrunch.comEight Sleep raises $86M as its smart mattress and ‘sleep fitness’ technology approaches $500M valuationSupports Series C valuation context, additional investor names, total funding at the time, and four-founder attribution including Andrea Ballarini.
axios.comEight Sleep raises $100 million, preps retail storesSupports 2025 $100M Series D, investor list, FDA application plans, retail-store plans, and Asia expansion plans.
wsgr.comFirm Advises Eight Sleep on IP Matters Related to $100 Million FinancingSupports 2025 $100M financing, participants including HSG, Valor, Atreides, Founders Fund, Y Combinator, Charles Leclerc, and Zak Brown, and intended use for Sleep Agent and medical applications.
techcrunch.comEight Sleep raises $100M to expand its AI-powered sleep techSupports 2025 $100M funding, product details, $500M+ Pod sales, 10x revenue growth since 2019, one-billion-hour sleep-data claim, team size, and international shipping footprint.
techcrunch.comEight Sleep raises $50M at $1.5B valuationSupports March 2026 $50M strategic round led by Tether Investments, $1.5B valuation, total funding context, free-cash-flow positive claim, and 34+ country shipping footprint.
tether.ioTether Makes Strategic Investment in Eight Sleep at $1.5B to Accelerate Sustainable Health IntelligenceSupports Tether Investments' strategic investment, $1.5B valuation, and collaboration around AI-driven health technology and QVAC architecture.
eightsleep.comWhy Eight SleepSupports the company's science-backed positioning, biometric monitoring features, and sleep-improvement claims.
eightsleep.comNew Funding, New OpportunitiesOfficial company post supporting the 2019 $40M funding led by Founders Fund with participation from Khosla Ventures, Y Combinator, Craft Ventures, 8VC, Ryan Petersen, Kevin Hartz, and Jason Calacanis.
businesswire.comEight Sleep Raises $86M Series C to Scale Sleep Fitness MovementSupports the 2021 Series C, company description, named investors, and revenue growth claims at that time.
businesswire.comEight Sleep Secures $100 Million to Accelerate AI‑Powered Sleep Optimization, Expand Into Medical, and Grow Global FootprintSupports the 2025 $100M financing, participants, $500M+ Pod sales, 10x revenue growth since Pod launch, 1B+ hours of sleep data, and 30+ country footprint.