How the Silo works

1 xSEED=backing÷xSEED supply

The backing is the $SEED the Silo holds, plus the $SEED it has lent out, minus the $SEED waiting to be burned. Divided by the number of xSEED, it gives the net asset value of one xSEED in $SEED. That is the price the site shows.

It never goes down. Every action leaves at least as much $SEED behind each xSEED as before:

• A deposit mints xSEED for 97.5% of what comes in. 70% of the fee joins the backing.
• A withdrawal pays out 97.5% of what the xSEED are worth. 70% of the fee stays in the backing.
• Loan interest is paid up front, and 70% of it joins the backing.
• An unpaid loan burns xSEED that were worth more than the debt it erases.
• The 30% of each fee that gets burned is set aside, outside the backing, the moment it is paid.

The price is counted in $SEED. If $SEED falls in dollars, xSEED falls in dollars too.

Approve the Silo for your $SEED, then deposit. You receive xSEED at the price of the moment, minus a 2.5% fee.

xSEED received=(amount - 2.5%) ÷ price

The price can only rise between your quote and your transaction, so you may get slightly fewer xSEED than quoted. The site accepts up to 0.5% fewer. Past that, the transaction fails and nothing is taken.

A deposit can credit another wallet: the contract takes a recipient address.

Give xSEED back and receive $SEED at the price of the moment, minus a 2.5% fee. Any amount, at any time. There is no lock and no queue.

Your xSEED are burned. 70% of the fee stays in the Silo, so the price goes up for everyone who stays.

A deposit followed by a withdrawal pays both fees: at the same price, 1,000 $SEED comes back as 950.62. xSEED has to grow about 5.2% before a round trip pays.

Lock xSEED and borrow up to 99% of their value in $SEED, for 0 to 365 days.

interest=loan × (0.1% + 3.9% × days ÷ 365)

The days are counted from today, today included. The interest is taken from the loan when you borrow: you receive the loan minus the interest, and you owe the full loan.

Your loan ends at 00:00 UTC after its last day. A 30-day loan taken on November 6 ends on December 7 at 00:00 UTC. A 0-day loan ends at the next 00:00 UTC.

There is no liquidation price. xSEED can't go down, so the xSEED you locked always cover what you owe, and nobody can close your loan because of the price. The only deadline is the end date.

Each wallet has one loan at a time. Your locked xSEED keep gaining while the loan runs.

Repay

Pay back part or all of the loan in $SEED. When you owe nothing, all your xSEED come back. Free.

Add days

Push the end date back, up to 365 days after today. Costs 3.9% a year on what you owe, for the days you add: about 32 $SEED to add 30 days to a 10,000 $SEED loan.

Borrow more

When xSEED has grown, or if you lock more xSEED, borrow up to 99% of the new value. Interest is charged on the extra amount only, for the days left.

Take back xSEED

Unlock spare xSEED, as long as what you owe stays within 99% of what is still locked. Free.

Close

End the loan with its own xSEED, no $SEED needed. Your locked xSEED are cashed in at the price of the moment, the loan is paid from that, and you receive the rest minus a 1% fee on their value.

If a loan reaches its end date without being repaid or extended, at 00:00 UTC its locked xSEED are burned and its debt is erased. The borrower keeps the $SEED they borrowed and loses the xSEED.

Everyone else gains. The burned xSEED were worth more than the debt they covered: the debt was at most 99% of their value when the loan was taken, and xSEED has only gone up since. The backing loses the debt, the supply loses more than that in value, so the price rises.

Expired loans are processed by the first deposit, withdrawal or loan action after midnight, or by anyone calling processExpired(). The Silo's page shows the loans ending in the next 28 days and how much the price gains if they aren't repaid.

A loop opens a leveraged position in one transaction. The Silo mints xSEED for your whole position, with a 1% fee instead of 2.5%, locks them as collateral and lends you 99% of their value. You pay only the difference, plus the loan interest.

you pay=position - loan + interest

To take the money out, close the loan with its own xSEED: they are cashed in at the price of the moment, the loan is paid from that, and you receive the rest minus a 1% fee.

Break-even is about +2.46% for a 30-day loop. Below that, closing returns less than you paid. If xSEED doesn't move at all, closing returns nothing. If the loan reaches its end date, its xSEED are burned like any other unpaid loan.

The 30% of each fee waits in the Silo, outside the backing, until someone sends it to the dead address 0x000000000000000000000000000000000000dEaD. Anyone can do it: it's the "Burn it now" button on the Silo's page, or flushBurn() on the contract.

$SEED sent there can never move again. Each burn takes it out of circulation for good, and the Silo's page counts the total.

Midnight burns are a different thing: they burn xSEED, not $SEED. What those xSEED were worth beyond their debt stays in the Silo, for everyone else.

The contract has no owner, no pause, no admin mint and no upgrade path. $SEED leaves the Silo in four ways only:

• a holder withdraws, at the price of the moment minus the fee;
• a borrower takes a loan, at most 99% of what their locked xSEED are worth;
• a borrower closes a loan and receives what their xSEED are worth beyond the debt, minus the fee;
• the burned 30% of fees goes to the dead address.

The Silo opens with a first deposit whose xSEED go straight to the dead address. Nobody can ever withdraw that $SEED.

39 tests check the contract. Five properties are checked after every call of a random sequence, 200,000 calls per property in the long run:

• the price never goes down;
• the $SEED in the Silo always covers every xSEED that isn't locked in a loan;
• the $SEED waiting to be burned is always there;
• the total lent out never exceeds what the locked xSEED are worth;
• the totals always match the open loans.

The contract has not been audited.