A sealed venue on Hedera
Sotto is a request-for-quote venue for block trades in tokenised securities. A bondholder puts size up for bid; dealers quote under commit–reveal, so nobody can last-look off a competitor. The winning trade settles as one atomic delivery-versus-payment transaction — security leg and cash leg, both or neither.
| Dealer | Commit hash |
|---|---|
| Dealer A | 0x8d2ae03cd8e7… |
| Dealer B | 0x4c90cf5b62ed… |
| Dealer C | 0x2d87e21e0230… |
| Dealer D | 0xba9a9572f5da… |
The mechanism
The seller places an ATS hold naming the settlement contract as escrow agent. Available drops, Held rises, and Total does not move — the block never leaves the seller’s account, and coupons keep accruing on all of it.
If nothing is awarded, anyone may reclaim the hold directly from ATS.
Dealers submit keccak256(price, quantity, nonce, dealer). Only the hash reaches the ledger. The window closes on a Hedera consensus timestamp rather than our clock, and every reveal is recomputed against its commit.
A price that can be changed after the window closes is not a sealed quote.
Both parties sign an EIP-712 trade. One transaction moves the cash and executes the hold. ATS runs compliance inside the delivery — so a revoked KYC rolls back the payment with it.
That is the difference between a settlement system and a token transfer.
Deployed on Hedera testnet
Nothing here is mocked and nothing was minted for convenience: the bond is issued from Hedera's own ATS factory, and the cash leg settles in real Circle USDC.
Open for quotes, or in the reveal window
reading /api/health…