Trade: Seattle Mariners vs. Houston Astros
Resolution criteria on PolyGram: In the upcoming MLB game between the Seattle Mariners and Houston Astros, scheduled for May 12 at 8:10PM ET: This market will resolve to "Seattle Mariners" if the Seattle Mariners win the game. This market will resolve to "Houston Astros" if the Houston Astros win the game. If the game is postponed, this market will remain open until the game has been completed. If the game is canceled entirely, with no make-up game, or ends in a tie, this market will resolve 50-50. The primary resolution source for this market is the official final statistics of the event as recognized by the governing body or event organizers.
PolyGram is an on-chain prediction market where you trade YES or NO outcome shares with real USDC on Polygon. For this market, buy YES if you believe the event will happen, or NO if you think it won't. Your maximum loss is your stake — winning shares pay $1.00 each at resolution. Unlike sportsbooks, there is no house edge: prices are set by supply and demand from other traders and reflect the crowd's real-time probability.
- Liquidity
- $12K
- Total Volume
- $25
- 24h Volume
- $25
- Open Interest
- $22
Market outcomes
| Seattle Mariners vs. Houston Astros | 57% YES | 43% NO |
| NRFI | 53% YES | 47% NO |
Market context
The Seattle Mariners travel to Houston for an AL West matchup on 12 May at 8:10 PM ET. The Polymarket order book currently reflects a 57% implied probability for a Mariners victory, suggesting modest favouritism despite Houston's home-field advantage. This probability will shift based on real-time betting activity through the settlement window closing on 20 May.
Historically, the Astros have maintained a slight edge in head-to-head records against the Mariners over recent seasons, though Seattle has shown competitive strength in divisional play. The 57% probability for the visiting Mariners indicates market participants are pricing in factors beyond home-field advantage—likely roster composition, recent form, and pitching matchups. For context, similar AL West road games typically settle between 45–55% for the visiting team absent significant injury news or exceptional recent performance streaks.
Key variables traders should monitor include starting pitcher announcements, which typically arrive 24–48 hours before game time, and any roster changes due to injury or roster moves. Recent performance trends matter considerably; either team's win-loss record in their preceding ten games could shift the probability materially. Weather conditions at Minute Maid Park—particularly temperature and humidity affecting ball carry—occasionally influence totals markets but rarely shift moneyline probabilities beyond 2–3 percentage points. The order book depth on Polymarket will reveal whether the current 57% reflects genuine consensus or sparse liquidity at that price level.
Wikipedia Context
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Seattle MarinersThe Seattle Mariners are an American professional baseball team based in Seattle. The Mariners compete in Major League Baseball (MLB) as a member club of the American League (AL) West Division. The team joined the American League as an expansion team in 1977, originally playing their home games in the Kingdome. Since July 1999, the Mariners' home ballpark ha
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Seattle Mariners minor league players
Below is a partial list of minor league baseball players in the Seattle Mariners system.
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Seattle Mariners award winners and league leaders
The following is a list of Seattle Mariners professional baseball players and managers who have won various awards or other accolades from Major League Baseball or other organizations or have led the American League in some statistical category at the end of the season.
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Seattle Mariners all-time roster
The following is a list of players, both past and current, who appeared at least in one game for the Seattle Mariners franchise.
Resolution source
This market settles from the official outcome published at https://www.mlb.com/. A proposer submits the final result to the UMA optimistic oracle on Polygon; the two-hour dispute window closes and payouts clear in USDC.
How to trade this market step by step
The mechanics for trading "Seattle Mariners vs. Houston Astros" are the same as any other PolyGram sporting event contract. Each YES share resolves to $1 if the event happens, or $0 if it doesn't. The current price between 0¢ and 100¢ is the market's probability estimate, set live by the order book.
- Sign in on polygram.ink with your email — no full KYC under $1,500 lifetime trading volume.
- Deposit USDC on Polygon (lowest fees, ~$0.01 per transaction) or Ethereum. Funds credit after 12 confirmations.
- Pick a side. Buy YES if you believe the event will happen; buy NO if you think it won't. The current YES price reflects the market's collective probability.
- Size your position. If you stake 100 USDC at 50% YES, you'll receive shares that pay $200 if YES resolves true — a 100% gross return. If NO resolves, your shares are worth $0.
- Set risk controls (optional). Stop-loss, take-profit, and limit-order types all supported. Use the trade ticket's slippage box to cap your maximum entry price.
- Wait for resolution. When the event resolves on-chain via the UMA optimistic oracle, the winning side settles to 100¢ automatically and USDC hits your balance within seconds. Withdrawable to any wallet you control.
How active is this market?
$25 in lifetime turnover and $12K of resting liquidity puts this market in the below the median by volume for sports contracts on PolyGram. Order-book depth is modest — expect a couple of cents of slippage on $1k+ trades.
Last 24 hours alone saw $25 in turnover, well above the lifetime daily-average for this market — a clear sign of news catalysing trader activity right now.
The market has been open for under a month — fresh enough that information asymmetry remains a real factor.
Higher-volume markets tend to have tighter spreads and faster price discovery — meaning the displayed YES/NO percentages are more likely to reflect the true crowd-implied probability rather than a single trader's directional view.
Key terms
- YES / NO share
- A binary outcome token that pays $1.00 if the underlying claim resolves true (YES) or false (NO), and $0 otherwise. The market price between 0¢ and 100¢ is the implied probability.
- CLOB
- Central limit order book. The matching engine that pairs YES buyers with NO buyers (effectively the same trade). Polymarket's CLOB on Polygon executes trades on-chain via the conditional-tokens framework.
- Liquidity
- USDC capital sitting in resting limit orders inside the order book. Deeper liquidity means smaller slippage on large trades and a tighter bid-ask spread.
- UMA optimistic oracle
- The on-chain dispute system that settles each Polymarket market. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution.
- Slippage
- The difference between the displayed mid-price and your fill price. Affects market orders most; limit orders avoid slippage but may take time to fill.
- Conditional token
- ERC-1155 outcome share issued by Gnosis Conditional Tokens on Polygon. The token type that resolves to $1.00 or $0.00 at settlement.
Frequently asked questions
How does this market resolve?
Resolution is sourced from https://www.mlb.com/. Settlement is executed by the UMA optimistic oracle on Polygon, with a 2-hour dispute window before payouts clear.
When does this market close?
This prediction market is scheduled to close on 20 May 2026. After the resolving event occurs, settlement typically clears within 24 hours once the UMA optimistic oracle confirms the outcome. All payouts are in USDC on the Polygon network.
How can I trade on "Seattle Mariners vs. Houston Astros"?
To trade on this prediction market, create a free PolyGram account at polygram.ink, deposit USDC via Polygon, and place a YES or NO order on the outcome you believe in. You can learn more on our how-it-works page. Your maximum loss is limited to your stake — there is no leverage or margin.
What happens when the market resolves?
When the outcome is determined, winning YES shares pay out $1.00 each in USDC, while losing shares pay $0. Settlement is handled by the UMA optimistic oracle on Polygon — a proposer submits the result, a two-hour dispute window opens, and if uncontested, payouts are distributed automatically. You can withdraw your winnings to any Polygon wallet.
Risk and regulatory note
Prediction-market positions can lose 100% of staked capital. Outcomes are uncertain by definition — historical accuracy of crowd-implied probabilities is high in aggregate but not for any single market. PolyGram does not provide investment advice. Trade only with capital you can afford to lose.
Regulatory status varies by jurisdiction. Germany, the United States, and most EU countries treat Polymarket-style event contracts under one of three frameworks: financial derivative, gambling product, or unregulated novel asset. Consult local counsel before trading.
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