Eight Sleep has raised US$50m at a US$1.5bn valuation as the sleep technology startup moves to expand into artificial intelligence-driven health.
The round was led by Tether Investments as a “strategic” investment in the New York-based company.
The startup has now raised more than US$250m in total funding.
Co-founder and chief executive officer Matteo Franceschetti said: “Sleep was just the beginning.
“We’ve built the most advanced AI-powered health sensing system in the world, one that learns your body better every night and acts on that knowledge.
“This investment gives us the resources to take that intelligence beyond the bedroom and into every dimension of personal health.
“Our goal is to build the defining health technology company of this generation.”
Eight Sleep raised US$100m last August, marking its second funding round within a year.
At the time, the company was valued at US$1bn, up from about US$500m when it completed its US$86m Series C round in August 2021.
Founded in 2014, Eight Sleep describes itself as a sleep technology company that combines technology, physiology and data “to unlock deeper sleep and better health.”
The company initially launched the Pod, a smart mattress that uses embedded sensors to collect data and analyse sleep trends.
In 2018 it introduced an AI-powered sleep coach that provides personalised feedback.
The system may tell users things such as “Last night, you slept 40 minutes less than your average this month” or suggest going to bed earlier if REM sleep levels are lower than usual. REM sleep is a stage of sleep linked to memory and recovery.
Eight Sleep said the new capital will support its move from sleep optimisation into what it describes as predictive, AI-driven health.
Eight Sleep is not the only sleep-focused company to raise funding in recent years.
Investors have poured hundreds of millions into companies developing treatments for sleep-related conditions and technologies designed to improve sleep quality.
Oura, which produces wearable rings that record and analyse biometric data, has raised US$1.25bn in equity funding to date, including a US$900m Series E round at a US$11bn valuation in October 2025.