Italian football clubs, Argentine agricultural firms, brain chips — Tether has invested in them all.
Now, the world’s largest stablecoin issuer is betting big on mattresses.
On Wednesday, the company invested an undisclosed amount in Eight Sleep at a $1.5 billion valuation.
Eight Sleep’s mattresses and covers have grown popular among tech crowds for their personalised sleep insights generated by a network of sensors inside their products.
Tether, which is also investing heavily in artificial intelligence, expects to marry Eight Sleep’s products with the stablecoin firm’s data infrastructure.
Tether issues the dollar-pegged stablecoin, USDT. The token is worth more than $183 billion as of Wednesday afternoon.
The token is the largest of its kind and the third largest cryptocurrency, after Bitcoin and Ethereum.
Founded in 4, Tether’s business has boomed. As the underlying assets have historically been commercial paper, gold, and billions of dollars in US Treasuries, Tether has steadily generated enormous profits in the last few years simply by collecting the yield on American debt.
In 2025, Tether reported $10 billion in net profit, according to its own accounts.
Naturally, with such a vast war chest, the company has been eager to expand beyond its investment horizons.
Eclectic investment portfolio
The investment in Eight Sleep is yet another scatter-shot bet on sectors far beyond cryptocurrencies.
In 2024, Tether invested $200 million for a majority stake in Blackrock Neurotech, which is developing a type of brain-computer interface.
The company has also explored robotics, participating in an $81 million round in the Italian humanoid upstart Generative Bionics in December 2025.
The tie to Eight Sleep, however, rests in Tether’s health app launch, called QVAC Health.
Launched in 2025, the product uses artificial intelligence that runs locally on users‘ devices to help them track metrics such as heart rate, workouts, and, of course, sleep habits.
QVAC is pitched as an offline-capable app that skips the need for large, centralised cloud platforms.
Eight Sleep is expected to build out its own AI features on QVAC.
