Spark Savings on Arbitrum now supports the three largest stablecoins by market capitalization: USDC, USDS and, from today, USDT via USDT0.  For wallets, treasury platforms and other builders, that means users can access Spark Savings while staying in the stablecoin they already hold, through a single savings infrastructure. Here’s why this is important for the programmable economy future we’re building towards. 

Why this isn't "just another USDT deployment"

Arbitrum has bridged USDT for years. What's new is USDT0, Tether's omnichain implementation of USDT built on LayerZero's Omnichain Fungible Token (OFT) standard. Instead of yet another wrapped, fragmented representation of USDT moving around different bridges, USDT0 is a single, 1:1-backed unit of Tether liquidity that can move natively between Ethereum, Arbitrum, and a growing number of supported chains without fragmenting liquidity or introducing additional trust assumptions.

For integrators, that means supporting Spark Savings for USDT without asking users to bridge back to Ethereum, swap into another stablecoin or navigate multiple versions of USDT. Users can stay in the asset they already hold while accessing the same Spark Savings infrastructure available across supported stablecoins.

spUSDT is Spark's ERC-4626 USDT savings vault. Deposit USDT0, receive spUSDT, a transferable savings token that represents your position in the vault while continuing to accrue yield.
Like Spark's existing USDC and USDS savings vaults on Arbitrum, spUSDT follows the same ERC-4626 design, giving integrators a consistent way to support savings across multiple stablecoins.

USDT0 (spUSDT) is designed to be simple to integrate and simple to use:

• No lockups, deposit and withdraw at any time

• Transferable and composable with other DeFi applications through the ERC-4626 standard

• Access to Spark's programmatic allocation framework, which coordinates capital across vetted DeFi venues.

• Earn sustainable yield without relying on temporary incentives

With USDT0 now supported, users can access Spark Savings directly from one of Arbitrum's most widely used stablecoins without changing assets first.

With USDC, USDS, and now USDT0 supported, Spark Savings on Arbitrum now provides savings infrastructure representing over 90% of the network's stablecoin supply, according to defillama. That gives builders access to savings infrastructure across the stablecoins their users are most likely to already hold.

For users, that means staying in the stablecoin they already hold without bridging back to Ethereum or swapping into another asset just to access savings. For wallets, treasury platforms and DeFi applications, it means broader stablecoin coverage through a consistent integration model.

That matters because USDT remains the world’s largest stablecoin by supply, while Arbitrum has become one of the deepest ecosystems for stablecoin trading, derivatives, and on-chain payments. Bringing Spark Savings to USDT0 expands that coverage, making it easier for builders to offer sustainable savings across the stablecoins their users already hold.

Whatever stablecoin you're already holding or trading with on Arbitrum, there's now a Spark vault for it.

Building on Arbitrum?

Whether you're building a wallet, treasury platform or DeFi application, Spark Savings can help make your business programmable by making it easy to offer savings across the three largest stablecoins on Arbitrum.

Talk to the Spark team to learn how Spark Savings can fit into your product. sarah@phoenixlabs.dev