Current implied probability
Up 63%
Market quality
32 / 100
Low quality24h Volume
—
Liquidity
$129.9
Low liquidityBid / Ask
27.0% / 99.0%
Spread
72.0 pt
Wide spreadComments
0
Market data
Updated 9 minutes ago
Sep 18, 26, 12:01 PM UTCSep 21, 26, 8:00 PM UTC
Trends
Related Markets
Related questions for context, not a comparison of equivalent contracts.
Will Anthropic’s valuation hit __ by December 31?
PolymarketLargest IPO by market cap in 2026?
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PolymarketAnthropic IPO Closing Market Cap (Middle Brackets)
LimitlessWill Anthropic IPO before OpenAI?
Manifold MarketsAnthropic vs OpenAI - higher valuation on December 31?
PolymarketRules
This market will resolve to "Up" if the official S&P 500 Index open price for S&P 500 (SPX) on September 21 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day.
- This market will resolve to "Down" if the official S&P 500 Index open price for S&P 500 (SPX) on September 21 is lower than the official S&P 500 Index closing price for SPX on the most recent prior trading day.
- E.g., ordinarily, a market on Monday would refer to the previous Friday for its most recent closing price, unless that Friday were a market holiday, in which case it would refer to Thursday, or the next most recent trading day.
- If the two prices are exactly equal, this market will resolve 50-50.
- Note that all figures will be rounded to the nearest cent using standard rounding.
- If SPX does not trade at all during the regular session, the market will resolve 50-50.
Open markets
Exchange
KALSHIBTC price on Sep 18, 2026 at 5pm EDT?
- $80,000 or above+97.0pt99%
- $80,500 or above+98.0pt99%
- $79,000 or above+95.0pt99%
+47 more outcomes
- Total Vol
- $6.3M
- 24h Vol
- $4.5M
POLYMARKETBitcoin above ___ on September 19?
- 68,000+0.2pt100%
- 70,000+0.4pt100%
- 72,000+0.7pt100%
+8 more outcomes
KALSHIETH price on Sep 18, 2026 at 5pm EDT?
- $2,570 or above+95.0pt99%
- $2,530 or above+92.0pt99%
- $2,490 or above+81.0pt99%
+47 more outcomes
- Total Vol
KALSHIHow high will BTC get in September?
- Above $80,000.0099%
- Above $82,500.00+52.0pt72%
- Above $85,000.00+34.0pt44%
+5 more outcomes
- Total Vol
- $1.8M
KALSHIBitcoin price at the end of 2026
- 75,000 to 79,999.99-0.8pt13.6%
- 80,000 to 84,999.99+0.9pt12.6%
- 70,000 to 74,999.99-2.0pt11.7%
+25 more outcomes
- Total Vol
KALSHISOL price on Sep 18, 2026 at 5pm EDT?
- $112 or above99%
- $110 or above+92.0pt99%
- $104 or above+84.0pt99%
+47 more outcomes
- Total Vol
- $130.2K
- ETH price range on Sep 18, 2026 at 5pm EDT?
- Ethereum above ___ on September 19?
- BTC price range on Sep 18, 2026 at 5pm EDT?
- Bitcoin above ___ on September 20?
- Will Anthropic’s valuation hit __ by December 31?
- Anthropic IPO by which date?
- Bitcoin price on September 19?
- How low will BTC get in September?
- XRP price at Sep 18, 2026 at 5pm EDT?
- Bitcoin above ___ on September 21?
- Bitcoin above ___ on September 22?
Frequently asked questions
- What are the current odds for S&P 500 (SPX) Opens Up or Down on September 21??
- Polymarket prices Up at 63% as of September 18, 2026.
- When does S&P 500 (SPX) Opens Up or Down on September 21? resolve?
- S&P 500 (SPX) Opens Up or Down on September 21? is scheduled to resolve on September 21, 2026.
- How is S&P 500 (SPX) Opens Up or Down on September 21? settled?
- Polymarket settles this market as follows: This market will resolve to "Up" if the official S&P 500 Index open price for S&P 500 (SPX) on September 21 is higher than the official S&P 500 Index closing price for SPX on the most recent prior trading day.