Docs — OpenMarket

What OpenMarket is

OpenMarket is a prediction market that settles in USDC on Solana. Each market asks a yes-or-no question about a stock — “Will NVDA close above $214 on Sep 18?” — and lets you buy YES or NO shares. When the question settles, every share on the winning side pays exactly 1 USDC; shares on the losing side pay nothing. A YES share priced at 62¢ means the market puts the odds around 62%.

OpenMarket is custodial: you deposit USDC into the platform treasury, trade instantly on your account balance with no transaction fees or wallet pop-ups, and withdraw back to any Solana wallet whenever you like. How that custody is protected is described honestly under Custody, trust and risks.

Getting started

Get a Solana wallet — Phantom, Solflare, Backpack or any Wallet-Standard wallet. On mobile, open this site inside your wallet app's browser.
Connect and sign in. Signing in is a free message signature (no transaction, no fee) that proves you control the wallet. Your wallet address is your account.
Deposit USDC from that same wallet to the treasury address shown under Deposit. It is credited once the transfer is finalized, usually under a minute.
Pick a market, choose YES or NO, enter an amount, check the quote and confirm. Fills are instant.

Deposits and withdrawals

Deposits

Send USDC (mint EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v) on Solana mainnet to the treasury address 5SkruJFGfLULihAsj3kZPf31g26Dzpzq4VVtDposGPHm. Deposits are matched to you by the sending wallet, so always send from the wallet you signed in with. A transfer from an unknown wallet is held aside rather than lost, and can be attributed by support. Only USDC on Solana counts: other tokens, other networks and bridged variants are not credited.

Withdrawals

Request a payout of any amount from 1 USDC to any Solana address (your connected wallet by default). Your balance is debited immediately and the treasury sends a USDC transfer, usually within a couple of minutes; it creates the destination's USDC account if needed and pays all network fees. Large withdrawals wait for an operator's approval. If a payout cannot be sent, the balance is refunded — never silently lost.

Shares: how a market is built

A market is an escrow on the ledger. Locking 1 USDC in it creates one YES and one NO share — a split. Exactly one side will pay 1 USDC at settlement, so a complete pair is always worth 1 USDC and can be merged back into 1 USDC at any time before settlement, fee-free. That is what keeps every share fully backed: the escrow always holds one USDC per outstanding pair.

Prices and the pool

Each market has a liquidity pool — an inventory of YES and NO shares supplied by its creator and anyone else who adds to it — that quotes a price from their ratio. The two prices always add to 1 USDC. Buying YES takes YES out of the pool and raises its price; selling lowers it. It is the same constant-product rule as a Uniswap-style exchange. Larger orders move the price more; the panel shows exactly how many shares you get and your average price before you confirm, and a slippage limit protects you if the pool moves in between.

Launching your own market

Press Launch a market, pick a stock, set the price line and the settlement date, and put up the opening liquidity (minimum $5). That deposit becomes the market's YES/NO pool at 50¢ / 50¢, and trading opens instantly. You can also take a position at launch.

As the creator you earn the 2% pool fee on every trade in proportion to your share of the pool, plus 1% of every redemption when the market settles. You can add to or remove your liquidity at any time; removing returns YES and NO shares (plus the fees earned), which you can sell, merge or hold. If the market settles lopsidedly the pool ends up holding the losing side — that risk is what the fee pays for. Every market gets a shareable link.

Questions are always “Will TICKER close above $X on DATE?” so that every market resolves from one public, indisputable number — the exchange's official close. Anyone may add liquidity to any market, not just its creator.

Buying and selling

Buy: pick a side and an amount in USDC. The pool takes its fee, converts the rest into pairs and hands you the side you chose. Sell: sell shares back to the pool at the current price any time before the market is resolved, including after trading has closed. Advanced: split USDC into pairs or merge pairs back yourself.

Fees

Fee	When	Who receives it
Pool fee — 2%	On every buy and sell, from the trade amount	Whoever supplied the pool's liquidity — usually the creator — pro rata
Rake — 3%	Only when winning shares are redeemed after settlement	1% house · 1% airdrop pot (locked one year) · 1% the market's creator
Deposits, withdrawals, split, merge	—	Free (the treasury pays network fees on payouts)

Wallets holding at least 100,000 $MARKET pay no rake. Invalid refunds are never charged. Rounding always favours the pool or the escrow by at most one millionth of a USDC.

Settlement

Trading closes at the start (UTC) of the observation date. The market resolves YES if the stock's official 4:00 PM New York close is strictly above the threshold, otherwise NO. Invalid is used only when the question cannot be answered fairly (a delisting, a data outage); every share then refunds at 50¢ — a full par refund of every pair — with no rake. Resolutions are performed by the operators from the exchange's published closing price and are visible on each market.

After resolution, open the market and press Redeem: winning shares are converted to USDC on your balance, which you can withdraw immediately.

Profiles

Once signed in you can set a username and photo from the wallet menu. Usernames are 3–20 letters, numbers or underscores and are unique, first come first served (case-insensitive). Profiles show wherever your address appears. They are cosmetic only.

Custody, trust and risks

Your USDC is held by the platform treasury while you trade. Every deposit, trade and payout is recorded on a double-entry ledger where transactions must balance to zero and balances cannot go negative — enforced by the database, not by application code — so value cannot be created or lost by a bug. The ledger's custody total is reconciled against the treasury's on-chain USDC balance, and the service refuses to start if custody is ever below what it owes.
You are trusting the operators with custody and with resolving markets. Withdrawals are automatic below an operator-set limit and reviewed above it. Only the payout worker holds the treasury key; the website never does.
Market risk: prices move against you, liquidity can be thin, and a share on the losing side is worth zero.
Send correctly: USDC only, Solana mainnet only, from the wallet you signed in with. Other assets are not credited.

FAQ

Why did my buy give me more shares than dollars I spent?: Because the side you bought was priced below 1 USDC. $10 of YES at 58¢ is about 17 shares, each paying 1 USDC if YES wins.
I deposited but my balance did not change.: Give it a minute for finality, then check that you sent USDC on Solana mainnet from the wallet you signed in with. Deposits from another wallet are held aside and can be attributed by support.
Can I get out before the market settles?: Yes — sell to the pool at the current price, or merge complete pairs for exactly 1 USDC.
Do I need SOL?: Only a little in your own wallet to send the deposit. Trading and withdrawals cost you nothing in network fees.
Is there a token?: Yes — $MARKET. Holders of 100,000 or more pay no rake, and 1% of every redemption accrues to an airdrop pot that unlocks one year after launch.

How OpenMarket works.