TAPER
TAPER is a market for stock options that end the same day, on Solana. Each listed stock token (NVDAx, AAPLx and TSLAx, the xStocks issued by Backed) has one vault. Holders deposit the token, the vault sells calls on it that expire at the close of the New York session that day, and traders buy those calls with USDC.
Nothing is carried overnight. Every call sold on a day is settled from the xStock's own Raydium pool price (its mean over the 15 minutes before the bell), the premium goes to the holders who were in the vault, and the next trading day starts from zero.
Who is on each side
| Side | What they hold | What they want | What they get |
|---|---|---|---|
| Holder | NVDAx, AAPLx or TSLAx | Income on shares they already own, without lending them out | The premium traders pay, every trading day |
| Trader | USDC | A small, defined bet on where a stock ends today | Paid the difference in shares when the stock ends above the strike |
The holder's worst case is the covered call's: if the stock rises above a strike, the vault gives up the rise above it on the calls it sold. It never owes more shares than it holds, because the program will not sell a call it cannot cover.
What the program enforces
- One market per listed xStock, created only for the three mints in the launch constants (
LISTINGSinconstants.rs). - One trading day per market per New York date. A day opens only during a regular session, from the pool's price (the higher of its price now and its 10-minute mean).
- Five strikes per day, fixed at listing: the price rounded up to the strike tick, then every half daily standard deviation above it.
- Calls sold across the five strikes never exceed the shares in the vault at listing (
cover). - Sales stop ten minutes before the close.
- Settlement uses the pool's mean price over the 15 minutes before 4:00:00 pm New York time, read from the pool's own on-chain history, so the settler has no choice of price.
- A 10% fee on top of every premium is spent, by a crank anyone can call, buying TAPER and burning it.
- Every price is read on chain from the xStock's Raydium pool against USDC. No oracle, no API key, no one to ask.
There is no admin key over prices, fees or feeds. Everything above is a constant compiled into the program.
Status
Live on Solana mainnet since October 18, 2026: program GvkhWyGwq6CBNV3aEt18voh3bj4dah8uQFHWqA7b3AM2, with one market each for NVDAx, AAPLx and TSLAx. The TAPER token does not exist yet, so fees collect in the burn account until it does.