"ETH/BTC Up or Down on May 21?" is a daily prediction market on Polymarket where traders buy and sell shares on whether Bitcoin's price will finish higher ("Up") or lower ("Down") than its opening price over the daily window specified in the title. The current market probability is 100% for "Down." A price of 100% means the market collectively assigns a 100% chance to that outcome. Prices update in real-time as traders react to live Bitcoin price movements. Shares in the correct outcome are redeemable for $1 each upon market resolution.

"ETH/BTC Up or Down on May 21?" is an active short-term market on Polymarket. Trading volume can accumulate quickly as the daily window progresses — jump in early to help set the odds before this window closes.

To trade on "ETH/BTC Up or Down on May 21?," decide whether you believe Bitcoin's price at noon ET on May 21 will be higher ("Up") or lower ("Down") than Bitcoin's price at noon ET on May 19. Buy "Up" if you think the price will rise day-over-day, or "Down" if you think it will fall. Enter your amount and click "Trade." If your chosen outcome is correct at resolution, each share pays out $1.00. If incorrect, shares are worth $0.

This daily window has closed and resolved. The final outcome was "Down." Use the time-range navigation bar at the top of this page to view adjacent windows or find the current live market.

The "ETH/BTC Up or Down on May 21?" market resolves based on a comparison of Bitcoin's price at noon ET on May 21 versus noon ET on May 19, using Binance BTC/USDT 1-minute candle close prices. If the May 21 noon price is higher, the outcome is "Up"; if lower, "Down"; if equal, the market resolves 50-50. You can review the complete resolution criteria and data source in the "Rules" section on this page.

Yes. You don't need to trade to stay informed. Each "ETH/BTC Up or Down on May 21?" page shows real-time Up/Down probabilities reflecting trader sentiment on whether Bitcoin will be higher or lower at noon ET tomorrow versus today. Use the date navigation features at the top of the page to browse past and upcoming daily windows. You can also view the Order Book and Activity tab for a real-time feed of trade flow.

Polymarket odds are set by real traders putting real money behind their beliefs. “ETH/BTC Up or Down on May 21?” is still building its trading base for this window, so the current Up/Down probabilities may reflect only a small number of trades. As more participants enter before the window closes, the odds will become increasingly robust. For the latest stats on Polymarket’s overall prediction accuracy, visit the accuracy page on Polymarket.

To place your first trade on "ETH/BTC Up or Down on May 21?," sign up for a free Polymarket account and fund it using crypto, a credit or debit card, or a bank transfer. Once your account is funded, return to this page — or navigate to the current active daily window using the navigation bar at the top of the page — select "Buy Up" or "Buy Down," enter your amount, and click "Trade." If the window shown in the title has already closed, use the navigation bar to find the current live window. If you're new to prediction markets, click the "How it works" link at the top of any Polymarket page for a quick step-by-step walkthrough.

On Polymarket, the price of each outcome represents the market's implied probability. A price of 100¢ for "Down" in the "ETH/BTC Up or Down on May 21?" market means traders collectively believe there is roughly a 100% chance that Bitcoin's price will finish down over this daily window. If you buy "Down" shares at 100¢ and Bitcoin finishes in that direction, you receive $1.00 per share — a profit of 0¢ per share. If Bitcoin moves the other way, those shares are worth $0. Prices can shift throughout the day as Bitcoin's price action unfolds toward the noon ET close.

This daily window closed at 8:00AM ET May 21 and has been resolved. The final outcome was "Down." Use the navigation bar at the top of this page to view adjacent windows or find the current live market.

The "ETH/BTC Up or Down on May 21?" market has 10 comments where traders share their analysis and react to live Bitcoin price movements. Scroll down to the comments section to read what other participants think. You can also check the "Activity" tab for a real-time feed of trades on this window.

Polymarket is the world's largest prediction market, where you can stay informed and profit from your knowledge of real-world events. Traders buy and sell shares on outcomes for topics ranging from politics and elections to crypto, finance, sports, tech, and culture — including daily Bitcoin direction markets like "ETH/BTC Up or Down on May 21?." Prices reflect real-time, crowd-sourced probabilities backed by financial conviction, often providing faster and more accurate signals than polls, pundits, or traditional surveys.