How USDD holds its peg

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Just minted and burned

USDD tokens tokens being burned keeper, bidding at auction a chain's ledger flashes as it settles USDD vaults: TRX, Smart Allocator, USDT, sTRX

A vault owner locks $150 M of TRX in a TRX vault and draws 90 M new USDD against it: a collateral ratio of 167 %. The vault must stay above 120 % (TRX-A; TRX-B and TRX-C use 117 % and 130 %). The debt accrues a 0.5 % yearly stability fee. The new USDD lands on TRON, where TRON's validators settle it.
Anyone can swap 50 M USDT for 50 M USDD through the peg stability module, and back. USDD's docs say swaps are free, and the fee for swapping in reads zero on-chain. If USDD trades under a dollar, buying it and swapping it for USDT earns the gap, which pulls the price back.
Holders pay each other on TRON and on Ethereum, each settled by its own chain. A holder on Ethereum deposits 20 M in sUSDD, the savings vault: the tokens are burned and the vault holds the claim, earning 4 % a year at the end of September 2026.
The owner pays back 30 M USDD. It is burned, the debt falls to 60 M, and a third of the TRX is released. The ratio stays at 167 %: the owner took out collateral in step with the debt.
The oracle price of TRX drops 30 % and the vault's ratio falls to 117 %, under its 120 % minimum. The Dog contract seizes it and a Clipper runs a falling-price auction that starts above market. A keeper buys the TRX, paying the debt plus a 13 % penalty in USDD, which is burned. The TRX left over goes back to the owner.
On September 30, 2026 USDD's own dashboard showed $2.26 B of collateral against 1.53 B USDD, sUSDD included: 52 % TRX in vaults, 44 % stablecoins lent out by the Smart Allocator, 3.5 % USDT in the PSMs. The vaults are on-chain; the valuation is the protocol's, not an auditor's.

Vault openings and auctions on TRON aren't streamed here; the gauge shows each TRON vault type's collateral ratio from USDD's API, every minute.

Supply by chain Reading supplies…

How this is read

USDD's token supply on TRON (TronGrid), Ethereum and BNB Chain (public nodes), plus the USDD held in sUSDD on Ethereum and BNB Chain, which the token supply leaves out. Together they match USDD's own headline figure. Use the arrow keys to read each row.

Minted and burned

minted, up
burned, down

What just happened (illustrative) 0 USDD in circulation 0 collateral 0 minted 0 burned 0 chains shown

The parts that make this work

What USDD is now

USDD is a dollar stablecoin from the TRON ecosystem. The current version, USDD 2.0, has run on TRON since January 2025 (its contracts were deployed on January 20), natively on Ethereum since September 2025 and on BNB Chain since October 2025. It's a fork of MakerDAO's system: the same Vat, Jug, Dog, Clipper, Spot and Vow contracts, with Chainlink and WinkLink price feeds. It has no blockchain of its own; a USDD balance is an entry in a token contract on each chain.

The 2022 token, now called USDDOLD, converts one for one into the new one through a migration contract, with no deadline. About 7.1 M of it was still outstanding in September 2026.

Vaults, ratios and the stability fee

Anyone can open a vault, lock collateral and borrow USDD up to the vault type's limit. The debt grows with a yearly stability fee; repaying it burns the USDD and unlocks the collateral. On September 30, 2026 the TRON vault types stood like this, according to USDD's API:

USDD vault types on TRON, September 30, 2026
Vault type	Minimum	Fee	Ratio now	Debt, USDD
TRX-A	120 %	0.5 %	247 %	171,086,697
TRX-B	117 %	0.5 %	254 %	95,779,401
TRX-C	130 %	0.5 %	266 %	190,605,124
sTRX-A	130 %	1 %	206 %	5,894,476
USDT-A	105 %	1 %	120 %	551,624

WBTC vaults on TRON and ETH and WBTC vaults on Ethereum exist but were empty. Source: USDD public API, read September 30, 2026.

The PSM and the Smart Allocator

The peg stability module swaps USDT (and USDC on Ethereum) for USDD one for one on TRON, Ethereum and BNB Chain. It held about 78.5 M USDT at the end of September 2026. It is the tightest link to the dollar: a USDD redeemable for a USDT is worth about a dollar as long as USDT is.

The Smart Allocator, running since June 2025, is a vault through which USDD's reserve stablecoins are lent to other protocols for yield. At the end of September 2026 it accounted for about $990 M, 44 % of all collateral: roughly $723 M in USDS on Spark, $116 M in USDT on Aave on Ethereum, $80 M in USDT on Spark, $50 M on JustLend, $46 M in USDT0 on Aave on Plasma and $3 M on Morpho. Its value depends on those protocols as well as on USDD's own contracts.

Liquidations

When a vault falls under its minimum ratio, anyone can call the Dog contract to seize it. A Clipper then sells the collateral in a Dutch auction: for TRX-A the price starts at 110 % of the oracle price and falls until a keeper buys. The keeper pays the debt plus a 13 % penalty in USDD, which is burned, and whatever collateral is left goes back to the owner. Whoever starts the auction earns 5 USDD plus 0.1 % of the debt. Each vault type has a cap on how much debt can be at auction at once (35 M USDD for each TRX type). When checked on September 30, 2026, TronGrid's event API returned no liquidation (Bark) events for the TRON Dog contract, so this page doesn't stream them.

sUSDD, the savings vault

sUSDD is a standard ERC-4626 vault on Ethereum and BNB Chain; there is none on TRON. Deposited USDD is burned and the vault's shares grow in value as interest accrues. The rate was 4.00 % a year on September 30, 2026. USDD's docs say it is set by a "dynamic APY pricing model" that looks at other stablecoin yields, the Fed rate and the Smart Allocator's returns. Because deposits leave the token supply, USDD's headline figure adds the sUSDD balance back in: 1.32 B tokens plus 206 M in savings made 1.53 B.

History

The first USDD launched on May 5, 2022 as an algorithmic stablecoin: TRX could be burned to mint USDD and the reverse, a design often compared with Terra's UST, and the TRON DAO Reserve advertised a 30 % yield. It slipped below its peg in June 2022, to about $0.97 on June 13 according to news reports and to a low of $0.928 on June 19 by CoinGecko's data, while the TRON DAO Reserve said it was deploying USDC and that collateral stood at over 200 %. It dipped below $0.97 again during the FTX collapse in November 2022.

In August 2024 the TRON DAO Reserve withdrew about 12,000 BTC from USDD's collateral without a vote, leaving it backed mostly by TRX; Justin Sun called it a capital-efficiency move. USDD 2.0 replaced the reserve with the vault system described here. CoinGecko's daily prices show USDD within about 1.2 % of a dollar over the year to September 2026.

Who controls it

USDD's terms of use name only the "USDD Team", and its governance page said in September 2026 that details would "be shared soon". On TRON, the Pause contract that can change the system's parameters has no timelock (its delay is zero) and answers to a proxy owned by a single ordinary account, which also deployed the contracts. This page checked only that path, not every contract's list of admins. The contracts were audited by ChainSecurity (January and October 2025) and CertiK (September 2025).

What live mode shows, and what the animation simplifies

Live mode reads USDD's token supply on TRON through TronGrid and on Ethereum and BNB Chain from public nodes, and the USDD in sUSDD from the vault contracts. On TRON it reads every USDD transfer, which is how it spots mints and burns; on Ethereum and BNB Chain it polls for them. Many mints and burns aren't new borrowing: a PSM swap mints, an sUSDD deposit burns. The collateral gauge and the vault fills come from USDD's own API, and the TRX price from CoinGecko. The animation draws each vault type as one box and a whole chain as a small ring of wallets. The step-by-step numbers are illustrative, about two thirds of the real system. Read USDD's documentation for the details.