Tether’s USDT has crossed the $150 billion market cap mark for the first time, extending the reach of the world’s largest stablecoin even as questions mount in Europe over its reserves and disclosures.

The milestone underscores how deeply USDT is embedded in crypto trading and payments, but it also arrives at a sensitive moment for the company. European regulators are increasing their attention on whether Tether’s backing and reporting meet the standards expected for a token used at global scale.

Stablecoins are designed to hold a steady value, usually pegged to a fiat currency, and USDT has long been a central tool for traders moving funds across exchanges. Its growth has made it a major fixture in the digital asset market, while also putting Tether under persistent pressure to prove that its claims of support are transparent and reliable.

The latest scrutiny reflects a broader push by regulators to bring greater oversight to crypto firms operating across borders. For Tether, the challenge is balancing rapid expansion with the demand for stronger accountability in one of the industry’s most closely watched products.