Save
Deposit USDG and get tUSDG back, an ordinary token that goes up in value as interest comes in.
- Earns through Steakhouse USDG on Morpho
- Withdraw any amount, any block
- Zero fee in the contract, and no owner to add one
Live on Robinhood Chain
Tarn
Keep your dollars. Let the interest buy stocks.
Deposit USDG and it earns the Morpho lending rate from the first block. Whenever you like, Tarn turns only what it earned into NVDA, Apple, the S&P 500 or any of 42 tokenized stocks. The dollars you put in never move.
3.87% on dollars, measured
Principal can't be harvested
No owner, no fee
3.87%
Yearly rate, last 7 days
—
In the Morpho vault behind it
—
Deposited in Tarn
42
Stocks you can buy
The problem
Saving and investing shouldn't be a choice
Dollars in a wallet earn nothing. Moving them into stocks means giving up the safety of dollars. Most people end up doing neither.
Before
Idle dollars, or all-in
- USDG sitting in a wallet pays no interest at all.
- Buying stocks means putting the savings themselves at risk.
- Recurring buys come out of your principal, every time.
- Lending protocols pay interest, but it just piles up there.
With Tarn
Savings that buy shares
- Your USDG earns the Morpho lending rate from the first block.
- Tarn records what you put in. That line is your principal.
- Anything above that line is interest, and only that can be harvested.
- Take it as dollars, or have it buy any tokenized stock in the same transaction.
What you can do
Save, grow, trade
Three things, all in one app, all on chain. Every figure you see is read from Robinhood Chain when the page loads.
Grow
One click turns only your interest into a stock of your choice. Your principal stays where it is.
- Pick from 42 tokenized stocks and ETFs
- You set the minimum you'll accept
- The contract won't pay out a cent of principal
Trade
Buy or sell any tokenized stock for USDG in one transaction, routed through the deepest Uniswap pool.
- Best fee tier picked per trade
- All-or-nothing: no half-filled orders
- A $1,000 buy costs 0.35% at the median
How it works
Four steps, one line in the sand
The contract keeps one number for you: what you put in. Everything above it is yours to spend. Nothing below it is.
01
Deposit
Send USDG to TarnVault. It goes straight into Steakhouse USDG on Morpho, and you get tUSDG back.
02
Earn
Borrowers pay interest into Morpho every block, so each tUSDG redeems for a little more USDG.
03
Harvest
Tap Grow. The vault works out value minus principal and burns only the tUSDG that difference is worth.
04
Own
That interest is swapped into the stock you picked and sent to your wallet in the same transaction.
A worked example
$10,000 in, a year later
At the rate Morpho paid over the last 7 days, $10,000 earns about $387 in a year. Harvest it into NVDA and you own the shares. The $10,000 is still there, still earning.
The rate is Morpho's, not ours, and it moves with borrowing demand. The figure uses the rate measured on 23 Sept 2026.
You deposit10,000.00 USDG
Principal recorded10,000.00 USDG
Worth after a year10,387.00 USDG
Harvestable interest387.00 USDG
Left earning10,000.00 USDG
Markets
Real stocks, real pools
These are Robinhood's own tokenized stocks. Prices come live from each stock's deepest USDG pool. The cost of a $1,000 buy was quoted by TarnSwap's own code against the same pool.
Security
What the contracts guarantee
Each property below is checked by a test that runs on Robinhood Chain itself, against the real USDG, the real Morpho vault and the real pools.
Principal can't be harvested
Harvest pays value minus principal and nothing else. It burns exactly the shares that interest is worth, rounded against the caller.
harvestCannotTouchPrincipal · harvestExactShares
Interest can't be faked
Sending tUSDG moves the same share of principal with it, so shuffling tokens between wallets creates no interest.
transferMovesPrincipal · transferFromMovesPrincipal
Donations don't reprice
Only the vault's Morpho shares count. USDG sent to it directly changes nobody's balance.
donationIgnored
No first-depositor trick
Six decimals of virtual shares mean a tiny first deposit plus a big donation can't round the next depositor down.
inflation
Swaps are all-or-nothing
A trade fills in full at or above your minimum, or it reverts. Only a genuine pool from the factory can collect payment.
partialFill · swapMinOut · callbackRejectsCaller
Nobody is in charge
No owner, no admin, no pause, no upgrade, no fee switch. The code at the address is the whole product.
no privileged function exists to test
Not audited. Tarn has not been through a third-party audit. It is two short contracts built on audited infrastructure (Morpho, Uniswap v3, OpenZeppelin), but you should only deposit what you can afford to lose.
FAQ
The short answers
Where does the interest come from?
From borrowers. TarnVault puts every deposit into Steakhouse USDG, a Morpho vault on Robinhood Chain holding about $494M. It lends USDG to borrowers who post collateral. Their interest raises the vault's share price, and so the value of every tUSDG.
What exactly is my "principal"?
The USDG you deposited, minus what you've withdrawn, in proportion. If you withdraw 30% of your tUSDG, 30% of your principal goes with it. If you send someone tUSDG, the same share of principal goes with it. Harvest can only pay out value above that line.
Can I lose money?
Yes. If Morpho borrowers default and their collateral doesn't cover the loan, the source vault takes the loss and so does tUSDG. Stocks you harvest into can fall. And these contracts are not audited. Tarn's own rules keep your principal out of harvests. They can't protect it from the market or from a bug.
Is there a lockup or a fee?
No lockup: withdraw any block, as long as Morpho has the liquidity to pay out, which it normally does. No fee: the contract has no fee variable and no owner who could add one. You pay gas, plus the pool's own trading fee when you buy a stock.
Which stocks can I buy?
42 of Robinhood's tokenized stocks and ETFs that have a USDG pool on Uniswap v3 able to fill a real order, including NVDA, AAPL, MSFT, TSLA, GOOGL, META, SPY and QQQ. See Markets for prices and what a $1,000 order costs in each.
Who controls Tarn?
Nobody. Both contracts are deployed through the standard CREATE2 deployer, so their addresses are fixed by their code. Whoever deploys them gets exactly the same contracts, and no one holds a key afterwards. The app checks that the code at each address hashes to this build.
What do I need to start?
A wallet like MetaMask or Rabby, a little ETH on Robinhood Chain for gas, and USDG. The app adds Robinhood Chain to your wallet for you.