Spark has integrated its USDT savings vault into the OKX app, allowing eligible customers to earn on-chain yield without opening an external wallet or bridging funds. OKX aggregates deposits and routes them into Spark Savings on X Layer, its Ethereum layer-2 network, where deposits remain in the shared vault contract rather than a segregated OKX pool. The vault rate is 3.5%, while Spark governance set a 750 million USDT supply cap and a 6% maximum yield. On X Layer, deposits use USDT0, LayerZero’s omnichain version of Tether’s token; native USDT is used on Ethereum. Spark targets a liquidity buffer equal to the greater of 10% of deposits or $1 million, capped at $10 million, with remaining capital deployed across approved venues including SparkLend, Morpho vaults and real-world asset strategies. Each dollar deposited receives 1:1 USDS backing through Sky’s allocation system. The product is available to eligible OKX users outside the European Economic Area and other jurisdictions restricted by OKX. Existing reporting placed Spark Savings’ total value locked at roughly $1.26 billion at the OKX launch, while Spark separately put its USDT savings balance at approximately $361 million, including $359.9 million in the Ethereum vault. The integration adds distribution scale but also exposes users to X Layer’s operator and upgrade risks, which Spark’s risk reviewers have highlighted.