One call a week, written against pooled NVDA Stock Tokens.
Deposit one tokenised stock, receive cNVDA shares. Each week a keeper writes an Overcall call against the idle collateral and lists it for USDG. Premium is paid only if a buyer fills the listing. A week with no buyer pays zero, and on a book this thin that is the most likely outcome — published as a row like any other week, not hidden as an error state.
What happens to your token in one week
Cycle → expiryThe keeper binds to Overcall's registry cycle, not to a wall clock. One pass, every week, in this order.
- You deposit. NVDA Stock Tokens in, cNVDA shares out, pro rata. While the vault is idle you can withdraw immediately.
- The vault writes. When the registry opens a cycle, idle collateral is locked in Valorem Clear and one call is written per whole token, at the nearest strike rung inside the out-of-the-money band. If no rung qualifies, nothing is written and the collateral sits for the week.
- The call is listed for USDG on Seaport, with the vault as the offerer. The book closes Friday 20:00 UTC. Until then a buyer may take it, or may not.
- Saturday 20:00 UTC, the call expires. It was never bought, or was bought and expired worthless, or was bought and exercised. Those are the only three endings, and they are unpacked below.
- Harvest. Whatever USDG arrived is collected: 5% of the premium to the fee Safe, the rest, including any strike proceeds in full, claimable pro rata by share. A withdrawal requested while the call was open settles here, not before.
How the week ends
Three endings. Which one you get is decided by the order book and by what holders of this week's calls do, not by anything the vault does.
Nobody bought
Most likelyThere is no dealer obliged to take the other side. The listing sat on a thin book and nobody filled it, so the week pays zero USDG and the unsold options are worthless after expiry. The collateral can still be assigned: the vault writes the same option series as other writers, and Valorem assigns exercises across all of them. If their buyers exercise, tokens can leave at the strike for strike USDG in a week that paid nothing. Whatever is not assigned comes back when the week closes.
Bought, expired worthless
Premium keptA buyer paid. The vault was credited 95% of the premium and Overcall took 5% inside the order itself. No exercise was assigned to the vault, so the collateral comes back when the week closes and the USDG is claimable after the protocol fee.
Bought and exercised
AssignedAssignment can take the collateral at the strike. You keep the premium and those tokens come back as strike USDG instead, with no protocol fee taken from it; the upside above the strike is gone for that week. Valorem assigns by bucket, so a week can be assigned in part, and v1 does not buy the tokens back.
Where the money goes
Cut the path at Seaport and you have the other week: nobody fills and the premium is zero. The collateral is still written into a series other writers share, so it can still be assigned if their buyers exercise; whatever is not assigned comes back when the week closes. Settlement never reads a price feed — whether the vault was assigned is decided by what holders of the series did and by Valorem's assignment, and the Chainlink feed is display and a gate on writing and listing, nothing more. The protocol fee is 5% of the premium and nothing else: strike proceeds from an assignment carry no fee, and a week that pays nothing is charged nothing.
The limits are compiled in
On chainThese are contract bounds, not intentions. An admin can move a knob inside them and cannot move them, so nobody can quietly start selling at-the-money calls against your collateral.
The keeper opens the week, signs the listing and closes the week. It never holds the option tokens and can never move funds. A Guardian can halt writes and cancel listings and nothing else; neither role can block an idle withdrawal or the close of a week. The full policy table, the fees, the phase machine and every contract address are on how it works. The venue is Overcall, a third party — Callhouse is not an options exchange and runs no book of its own.
Before you deposit
- Stock Tokens are debt securities issued by Robinhood Assets (Jersey) Limited. Not shares: no vote, no claim on the company, and the issuer's credit risk is yours. The issuer can freeze transfers, which can stop this vault writing, closing the week and paying out tokens. The token can also pause its own price oracle, which stops new writes and listings but not settlement. The legal page has the full form.
- Not available to US persons. The same perimeter applies here as to the Stock Tokens themselves. Nothing on this site is an offer or investment advice.
- The Callhouse contracts have not been audited. Valorem Clear was audited by Zellic under its former name; this vault was not. There is no proxy, so a fix means a v2 and a migration. The 20 NVDA launch cap is the honest measure of how much confidence that deserves.
- There is no protocol token, no points programme and no airdrop at launch. Depositing early accrues nothing but the USDG a buyer actually paid.
- An empty book, assignment (including in a week nobody bought), partial assignment, an issuer freeze, the Valorem fee switch and an outage into the Friday window are each written out on the risks page. Read it before the app.
One action
Depositing, withdrawing, this week's strike and every published week live in the app at app.callhouse.finance. This domain never asks for a wallet.