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Daily market read
Certainty reflects how much of this market we measured, not how good the market is.
Too much of the trading came from wallets we cannot yet identify, so participant-flow coverage is uncertain.
Use only as a review target. Current-card issues must clear before this price is used as evidence.
The diligence packet carries the memo language, audit chain, and the Markdown, PDF, and JSON exports for this market.
Open the diligence packetWhy this rating
Composite 53 · Do not cite
Measurement certainty
Low
1 measured · 3 modeled · 2 not assessed
Certainty reflects how much of this market we measured, not how good the market is.
No full-provenance CME signal is linked to this condition in the current ledger window; absence of a signal is not proof of coherence.
Resolution rules
Rules as stated by Polymarket, reproduced verbatim. Convexly has not independently reviewed them and does not endorse them; the rating's resolution-reliability pillar treats rule text as present but not independently reviewed.
This market will resolve to "Up" if the official S&P 500 Index closing price for S&P 500 (SPX) on Monday, August 31, 2026 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 closing price for S&P 500 (SPX) on Monday, August 31, 2026 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 specified closing 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. If either of the relevant days are shortened (for example, due to a market holiday schedule), the official closing price published by S&P 500 Index for that shortened session will still be used for resolution. If either of the relevant days have no official closing price (for example, due to a trading halt into the market close, system issue, delisting, or other disruption), the market will use the last valid on-exchange trade price of the regular session as the effective closing price. The resolution source for this market is the Wall Street Journal, specifically the Close values published by the WSJ under "Historical Prices". US: https://www.wsj.com/market-data/stocks EMEA: https://www.wsj.com/market-data/stocks/emea ASIA: https://www.wsj.com/market-data/stocks/asia
Experimental rating caveat
Market Trust Cards are experimental market-quality diagnostics, not compliance certifications or validated credit ratings.
What travels with this read
Market Trust is a canary preview: verdict cutpoints are operator-set, and each read is a dated, descriptive diagnostic of market quality, not a prediction of the outcome and not a claim about what the probability should be. A prospective calibration test is filed and matures on resolved outcomes.
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Create a free accountNone of the wallets in Convexly's provably-complete set has been observed trading this market. That is a statement about this set's observed footprint, not about who trades here.
Check any Polymarket wallet →Quote it verbatim. The number and how the set was chosen travel together; the method is frozen and the per-wallet table is public.
Convexly rates this polymarket market "S&P 500 (SPX) Up or Down on August 31?" as Do not cite, as of 2026-08-31 (UTC).
Per Convexly Market Trust, the polymarket market "S&P 500 (SPX) Up or Down on August 31?" is rated Do not cite as of 2026-08-31T16:55:14.186Z (UTC). The rating describes whether the quoted market price was a clean enough data object to cite at that timestamp. This citation is market diligence, not investment advice, not a trading instruction, not a forecast, and not proof that the market probability is correct. Daily read: https://www.convexly.app/markets/spx-up-or-down-on-august-31-2026
Canonical URL: https://www.convexly.app/markets/spx-up-or-down-on-august-31-2026
Boundary of this page
This daily read is market diligence, not investment advice, not a claim of absolute truth, and not proof that any trader should buy or sell. It answers whether this market price had enough substrate to cite, monitor, discount, or ignore at the as-of timestamp, with receipts attached in the diligence packet.
Executability scored as worse-of(spread, depth) from a single orderbook snapshot; the two were merged from the former liquidity + depth pillars to stop double-counting one correlated source.
Resolution source and rule text are present but not independently reviewed.
Participant flow inputs exist but do not meet identity-coverage floors; descriptive only.
One or more screen indicators flagged at a low level. A reason to look, not a finding about anyone.
3 linked artifacts; 0 missing hashes; 0 stale/failing sources.
How it adds up: composite = Σ(score × weight) / Σ(weight) across measured + heuristic pillars only. Pending and data-rights-blocked pillars are excluded from both numerator and denominator. Total contributing weight = 70.0.
Caveat: 2 pillars not assessed yet; the score will recompute as the substrate fills in.
Convexly is independent and is not affiliated with or endorsed by Polymarket or Manifold. Wallet and market data are derived from publicly available venue sources.
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