> ## Documentation Index > Fetch the complete documentation index at: https://docs.ocx.global/llms.txt > Use this file to discover all available pages before exploring further. # Binary options > 15-minute Up/Down contracts on OCX500 and OCXTECH: how they work, how they settle, and how to trade them on the website A binary option on OCX answers one question: **will the index finish the window above where it started?** An **Up** share pays **$1.00** if it does; a **Down** share pays **$1.00** if it does not. Prices are in cents, so a price is the market's probability: Up at 62¢ means the market sees a 62% chance of Up. ## The contracts | | | | - | - | | Underlyings | **OCX500** (`SPX`) and **OCXTECH** (`NDX`) | | Windows | 15 minutes, back to back on the UTC quarter hour (:00, :15, :30, :45) | | Price to beat (strike) | The reference at the window's open | | Orders close | 15 seconds before the window ends (the **cutoff**) | | Settlement | The reference at the window's end | | Payout | $1.00 a winning share, $0 a losing one | | Price | Whole cents, 1¢ to 99¢ a share; whole shares | | Collateral | Fully paid: you pay the price up front, never more | **Reference.** The reference is the bid/ask mid of the front OCX500 or OCXTECH future, sampled every second. The strike is the first sample at or after the open; the settlement value is the first sample at or after the end. **Who wins.** Up wins only if the settlement value is **strictly above** the strike. A tie, settlement exactly equal to the strike, pays **Down**. **Void.** If the reference is missing at a fixing (the futures market is closed or not quoting), the window is void and **every Up and Down share pays \$0.50**. Windows are only listed while the reference future is trading. ## Up, Down and the order book Each window has one order book, quoted in **Up** cents. Down is the other side of the same book: buying Down at 38¢ is the same trade as selling Up at 62¢, because one Up share plus one Down share always pays exactly \$1.00. When a buyer of Up and a buyer of Down meet, a new pair is created and their \$1.00 is held in escrow until settlement. When holders of both sides sell, the pair is retired and the escrow pays them. Every share is backed by escrow, so a payout never depends on anyone else's balance. ## Your money * Binary options trade from your **wallet** balance; there is no margin. * A buy reserves price × shares when you place it. Fills pay from that reserve; anything unfilled comes back when the order is cancelled, at the cutoff at the latest. * Selling closes shares you hold. You cannot sell shares you do not have: to bet against Up, buy Down. * Payouts are credited to your wallet automatically when the window settles. Every movement appears in your wallet history and account statement. * No trading fees on binary options during testnet. * If you have an open loan on the [borrow & lend books](https://docs.ocx.global/api-reference/borrow-lend.md), a binary buy must leave enough in your account to cover it, the same rule as a withdrawal. ## Trading on the website Open **Binary Options** in the app. **1. Pick the index and the window** The header selector switches between OCX500 and OCXTECH. The window bar under it shows recent windows with their outcome (↗ Up, ↘ Down), the **LIVE** window and the next ones. The header shows the live reference, the price to beat, how far the reference is from it, and the time to the cutoff. **2. Read the book** The **BOOK** panel shows the live window's order book; switch it between Up and Down cents. **TRADES** shows the window's prints, and **MINE** your own fills. **3. Place an order in the ticket** Choose **Up** or **Down**, **Buy** or **Sell**, then **Market** or **Limit**. Enter the number of shares (or use 10 / 25 / 50 / 100 / Max). A market order fills against the book up to your slippage (1¢, 2¢ or 5¢) and cancels any rest; a limit order rests at your price until it fills, you cancel it, or the cutoff. The ticket shows the average price, the cost, what the shares pay if right, and the profit. **4. Or use 1-Tap** Switch **1-TAP** on in the header and set an amount ($10, $25, $50, $100 or your own). Clicking an **Up** or **Down** price in the **BINARY WATCH** table then buys that amount at market immediately, with 2¢ of slippage. With 1-Tap off, the same click loads the ticket instead. **5. Follow your positions** The bottom panel lists **Positions** (with average entry, value and what they pay), **Open Orders** (cancel from here), **Settled** windows and **Trade History**. > [!NOTE] > > Orders are refused from the cutoff onward. Anything still resting at the cutoff is cancelled and its reserve returned. To trade or make markets programmatically, see the [binary options API](https://docs.ocx.global/binary/api.md) and [quoting for market makers](https://docs.ocx.global/binary/market-makers.md). This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.