The Prediction Markets

Which company has the best Code Arena WebDev AI model end of December?

Closes
Jan 1, 2027, in 57 days
Traded
$1.2M
Venues
Polymarket, Kalshi
Prices updated
54 min ago
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What the markets expect

Anthropic 61.7%

Next is OpenAI at 13.5%. The venues differ most on Anthropic (Polymarket 66.5%, Kalshi 77%), a 10-point gap.

Anthropic 61.7%OpenAI 13.5%Meta 4.8%Google 4.6%ByteDance 4%14 others 11.4%

Odds by venue

Fair chance strips out each venue’s built-in margin (its prices add up to more than 100%), then blends the venues by how much has traded there, so the outcomes add up to 100%. Best Yes price is the cheapest ask across venues, and the payout is what a winning $100 stake returns before fees. Open a row for each venue’s contract name, bid and ask, and how closely their rules match.

Prices come from our regular polls of each venue, the oldest 54 min ago. Ages are as of when this page was built.

  • Polymarket
  • Kalshi
Anthropic
61.7%
Polymarket 66.5%(52.5% fair)polled, 54 min agoKalshi 77%(64.5% fair)polled, 54 min agoBest Yes 70¢ on Polymarket, $100 pays $143 (1.43x)
Polymarket
Contract
Anthropic
Last price
66.5%
Fair, margin removed
52.5%
As of
Polled 54 min ago
Buy Yes
70¢
Sell Yes
63¢
$100 on Yes pays
$143 (1.43x)
Volume
$2K
Trade this on Polymarket
Kalshi
Contract
Anthropic
Last price
77%
Fair, margin removed
64.5%
As of
Polled 54 min ago
Buy Yes
77¢
Sell Yes
75¢
$100 on Yes pays
$130 (1.30x)
Volume
$278K
Trade this on Kalshi
Same label, rules unverified

Labels suggest the same named outcome; no persisted outcome identity or settlement parity is verified.

Indicative only, prices are 54 min old: Buying on Polymarket at 70¢ and selling on Kalshi at 75¢ nets 500 bps before fees.

OpenAI
13.5%
Polymarket 23.5%(18.6% fair)polled, 54 min agoKalshi 14%(11.7% fair)polled, 54 min agoBest Yes 17¢ on Kalshi, $100 pays $588 (5.88x)
Polymarket
Contract
OpenAI
Last price
23.5%
Fair, margin removed
18.6%
As of
Polled 54 min ago
Buy Yes
27¢
Sell Yes
20¢
$100 on Yes pays
$370 (3.70x)
Volume
$1K
Trade this on Polymarket
Kalshi
Contract
OpenAI
Last price
14%
Fair, margin removed
11.7%
As of
Polled 54 min ago
Buy Yes
17¢
Sell Yes
14¢
$100 on Yes pays
$588 (5.88x)
Volume
$224K
Trade this on Kalshi
Same label, rules unverified

Labels suggest the same named outcome; no persisted outcome identity or settlement parity is verified.

Indicative only, prices are 54 min old: Buying on Kalshi at 17¢ and selling on Polymarket at 20¢ nets 300 bps before fees.

Meta
4.8%
Polymarket 6.1%(4.8% fair)polled, 54 min agoBest Yes 11.4¢ on Polymarket, $100 pays $877 (8.77x)
Polymarket
Contract
Meta
Last price
6.1%
Fair, margin removed
4.8%
As of
Polled 54 min ago
Buy Yes
11.4¢
Sell Yes
0.8¢
$100 on Yes pays
$877 (8.77x)
Volume
$397
Trade this on Polymarket
Google
4.6%
Polymarket 7.5%(5.9% fair)polled, 54 min agoKalshi 5%(4.2% fair)polled, 54 min agoBest Yes 6¢ on Kalshi, $100 pays $1,667 (16.7x)
Polymarket
Contract
Google
Last price
7.5%
Fair, margin removed
5.9%
As of
Polled 54 min ago
Buy Yes
13¢
Sell Yes
2¢
$100 on Yes pays
$769 (7.69x)
Volume
$557
Trade this on Polymarket
Kalshi
Contract
Google
Last price
5%
Fair, margin removed
4.2%
As of
Polled 54 min ago
Buy Yes
6¢
Sell Yes
5¢
$100 on Yes pays
$1,667 (16.7x)
Volume
$212K
Trade this on Kalshi
Same label, rules unverified

Labels suggest the same named outcome; no persisted outcome identity or settlement parity is verified.

Indicative only, prices are 54 min old: No arbitrage: the best bid elsewhere is 2¢, at or below the cheapest ask of 6¢.

ByteDance
4%
Polymarket 5.1%(4% fair)polled, 54 min agoBest Yes 9.6¢ on Polymarket, $100 pays $1,042 (10.4x)
Polymarket
Contract
ByteDance
Last price
5.1%
Fair, margin removed
4%
As of
Polled 54 min ago
Buy Yes
9.6¢
Sell Yes
0.5¢
$100 on Yes pays
$1,042 (10.4x)
Volume
$631
Trade this on Polymarket
Moonshot
1.8%
Polymarket 2.3%polled, 54 min agoBest Yes 3.5¢ on Polymarket, $100 pays $2,857 (28.6x)
Polymarket
Contract
Moonshot
Last price
2.3%
As of
Polled 54 min ago
Buy Yes
3.5¢
Sell Yes
1¢
$100 on Yes pays
$2,857 (28.6x)
Volume
$720
Trade this on Polymarket
xAI
1.7%
Kalshi 2%polled, 54 min agoBest Yes 3¢ on Kalshi, $100 pays $3,333 (33.3x)
Kalshi
Contract
xAI
Last price
2%
As of
Polled 54 min ago
Buy Yes
3¢
Sell Yes
2¢
$100 on Yes pays
$3,333 (33.3x)
Volume
$187K
Trade this on Kalshi
Alibaba
1.4%
Polymarket 3.8%(3% fair)polled, 54 min agoKalshi 1%polled, 54 min agoBest Yes 1¢ on Kalshi, $100 pays $10,000 (100x)
Polymarket
Contract
Alibaba
Last price
3.8%
Fair, margin removed
3%
As of
Polled 54 min ago
Buy Yes
6.6¢
Sell Yes
1¢
$100 on Yes pays
$1,515 (15.2x)
Volume
$467
Trade this on Polymarket
Kalshi
Contract
Alibaba
Last price
1%
As of
Polled 54 min ago
Buy Yes
1¢
Sell Yes
—
$100 on Yes pays
$10,000 (100x)
Volume
$52K
Trade this on Kalshi
Same label, rules unverified

Labels suggest the same named outcome; no persisted outcome identity or settlement parity is verified.

Indicative only, prices are 54 min old: No arbitrage: the best bid elsewhere is 1¢, at or below the cheapest ask of 1¢.

DeepSeek
1.4%
Polymarket 4%(3.2% fair)polled, 54 min agoKalshi 1%polled, 54 min agoBest Yes 2¢ on Kalshi, $100 pays $5,000 (50.0x)
Polymarket
Contract
DeepSeek
Last price
4%
Fair, margin removed
3.2%
As of
Polled 54 min ago
Buy Yes
5.6¢
Sell Yes
2.4¢
$100 on Yes pays
$1,786 (17.9x)
Volume
$519
Trade this on Polymarket
Kalshi
Contract
DeepSeek
Last price
1%
As of
Polled 54 min ago
Buy Yes
2¢
Sell Yes
—
$100 on Yes pays
$5,000 (50.0x)
Volume
$97K
Trade this on Kalshi
Same label, rules unverified

Labels suggest the same named outcome; no persisted outcome identity or settlement parity is verified.

Indicative only, prices are 54 min old: Buying on Kalshi at 2¢ and selling on Polymarket at 2.4¢ nets 40 bps before fees.

Baidu
0.9%
Kalshi 1%polled, 54 min agoBest Yes 1¢ on Kalshi, $100 pays $10,000 (100x)
Kalshi
Contract
Baidu
Last price
1%
As of
Polled 54 min ago
Buy Yes
1¢
Sell Yes
—
$100 on Yes pays
$10,000 (100x)
Volume
$16K
Trade this on Kalshi
Show 9 more outcomes
Moonshot AI
0.9%
Kalshi 1%polled, 54 min agoBest Yes 1¢ on Kalshi, $100 pays $10,000 (100x)
Kalshi
Contract
Moonshot AI
Last price
1%
As of
Polled 54 min ago
Buy Yes
1¢
Sell Yes
—
$100 on Yes pays
$10,000 (100x)
Volume
$82K
Trade this on Kalshi
Z.ai
0.7%
Polymarket 0.5%polled, 54 min agoKalshi 1%polled, 54 min agoBest Yes 0.9¢ on Polymarket, $100 pays $11,111 (111x)
Polymarket
Contract
Z.ai
Last price
0.5%
As of
Polled 54 min ago
Buy Yes
0.9¢
Sell Yes
0.1¢
$100 on Yes pays
$11,111 (111x)
Volume
$579
Trade this on Polymarket
Kalshi
Contract
Z.ai
Last price
1%
As of
Polled 54 min ago
Buy Yes
1¢
Sell Yes
—
$100 on Yes pays
$10,000 (100x)
Volume
$69K
Trade this on Kalshi
Same label, rules unverified

Labels suggest the same named outcome; no persisted outcome identity or settlement parity is verified.

Indicative only, prices are 54 min old: No arbitrage: the best bid elsewhere is 0.1¢, at or below the cheapest ask of 1¢.

MiniMax
0.4%
Polymarket 0.5%polled, 54 min agoBest Yes 0.9¢ on Polymarket, $100 pays $11,111 (111x)
Polymarket
Contract
MiniMax
Last price
0.5%
As of
Polled 54 min ago
Buy Yes
0.9¢
Sell Yes
0.1¢
$100 on Yes pays
$11,111 (111x)
Volume
$604
Trade this on Polymarket
Poolside
0.4%
Polymarket 0.5%polled, 54 min agoBest Yes 0.9¢ on Polymarket, $100 pays $11,111 (111x)
Polymarket
Contract
Poolside
Last price
0.5%
As of
Polled 54 min ago
Buy Yes
0.9¢
Sell Yes
0.1¢
$100 on Yes pays
$11,111 (111x)
Volume
$460
Trade this on Polymarket
SpaceXAI
0.4%
Polymarket 0.5%polled, 54 min agoBest Yes 0.9¢ on Polymarket, $100 pays $11,111 (111x)
Polymarket
Contract
SpaceXAI
Last price
0.5%
As of
Polled 54 min ago
Buy Yes
0.9¢
Sell Yes
0.1¢
$100 on Yes pays
$11,111 (111x)
Volume
$364
Trade this on Polymarket
Tencent
0.4%
Polymarket 0.5%polled, 54 min agoBest Yes 0.9¢ on Polymarket, $100 pays $11,111 (111x)
Polymarket
Contract
Tencent
Last price
0.5%
As of
Polled 54 min ago
Buy Yes
0.9¢
Sell Yes
0.1¢
$100 on Yes pays
$11,111 (111x)
Volume
$348
Trade this on Polymarket
Thinky
0.4%
Polymarket 0.5%polled, 54 min agoBest Yes 0.9¢ on Polymarket, $100 pays $11,111 (111x)
Polymarket
Contract
Thinky
Last price
0.5%
As of
Polled 54 min ago
Buy Yes
0.9¢
Sell Yes
0.1¢
$100 on Yes pays
$11,111 (111x)
Volume
$341
Trade this on Polymarket
Xiaomi
0.4%
Polymarket 0.5%polled, 54 min agoBest Yes 0.9¢ on Polymarket, $100 pays $11,111 (111x)
Polymarket
Contract
Xiaomi
Last price
0.5%
As of
Polled 54 min ago
Buy Yes
0.9¢
Sell Yes
0.1¢
$100 on Yes pays
$11,111 (111x)
Volume
$349
Trade this on Polymarket
Mistral
0.2%
Polymarket 0.3%polled, 54 min agoBest Yes 0.5¢ on Polymarket, $100 pays $20,000 (200x)
Polymarket
Contract
Mistral
Last price
0.3%
As of
Polled 54 min ago
Buy Yes
0.5¢
Sell Yes
0.1¢
$100 on Yes pays
$20,000 (200x)
Volume
$318
Trade this on Polymarket

Indicative gap, prices are 54 min old: Anthropic asks 70¢ on Polymarket and bids 75¢ on Kalshi (500 bps). Recheck both venues before trading. See all spreads

Mostly the same bet: one difference

Where they differ

  • Trading closes at different times: Jan 1, 2027, 4:59 AM UTC on Polymarket and Dec 31, 2026, 3:00 PM UTC on Kalshi.
Polymarket
Polymarket resolves via:
UMA optimistic oracle
Kalshi
Kalshi resolves via:
Kalshi (CFTC-regulated exchange), source: LiveBench.ai
Show full rule comparison
  • Trading closes Jan 1, 2027, 4:59 AM UTC on Polymarket and Dec 31, 2026, 3:00 PM UTC on Kalshi.

Summarized from each venue’s published rules; the venue’s own rules page is the final word.

How the odds have moved

The top 3 outcomes on both venues, with the consensus between them. Hover for exact values.

  • Anthropic
  • OpenAI
  • Meta

Live prices for Anthropic

What it costs to buy Yes, what you would get selling it, and the last trade on each exchange, updating as orders change. Hover a status for timing details.

Order books

Each venue’s resting orders for the selected outcome’s Yes contract, side by side. Top of book streams live; depth refreshes every 15 seconds.

Combined depth · both venues

Loading both order books…

Polymarket

Open on Polymarket ↗

Top of book

Connecting
Best bid
—
Spread
—
Best ask
—

Waiting for the first live quote…

Depth · top 8 levels

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Recent trades

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Kalshi

Open on Kalshi ↗

Top of book

Connecting
Best bid
—
Spread
—
Best ask
—

Waiting for the first live quote…

Depth · top 8 levels

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Recent trades

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What your stake buys

Enter a stake to see where it buys the most after fees, using each venue’s live order book.

$
Buy

Loading both order books…

Buys at the asks resting now (taker orders), cheapest after fees first, from order-book snapshots up to 15 seconds old. Fees: Kalshi 0.07 × price × (1 − price) per share, rounded up to the cent; Polymarket 0.05 × price × (1 − price) per share (other / general rate). Fee calculator. Estimates only, not advice.

About this market

Live prediction market odds for "Which company has the best Code Arena WebDev AI model end of December?". Anthropic leads at 61.7%. Next is OpenAI at 13.5%. $1.2M has traded across 19 outcomes on Kalshi and Polymarket. The market is expected to resolve by Jan 1, 2027.

This market will resolve according to the company that owns the model that has the highest rank based on the arena.ai Code Arena | WebDev Leaderboard when the table under "Code Arena | WebDev" filtered for "Models" is checked on December 31, 2026, 12:00 PM ET. Results from the "Rank" column under the "Code Arena | WebDev" Leaderboard tab at https://arena.ai/leaderboard/code/webdev (Overall) filtered for "Models" will be used to resolve this market. Note: Models marked “AutoEval” at the applicable check time will not be considered, regardless of whether they display a rank or score. Models will be ordered primarily by their leaderboard rank at the market’s check time. If two or more models are tied on rank, they will be ordered by which model is listed higher on the leaderboard. If a tie still remains, alphabetical order of company names as listed in this market group will be used as a final tiebreaker (e.g., “Google” would be ranked ahead of “SpaceXAI”). This market will resolve based on the company that occupies first place under this ranking. The resolution source for this market is the arena.ai Code Arena | WebDev Leaderboard. If this resolution source is unavailable at check time, this market will remain open until the leaderboard comes back online and will resolve based on the first check after it becomes available. If it becomes permanently unavailable, this market will resolve to "Other".

Questions

What does the consensus price mean?

It is the price of a Yes contract that pays $1 if the outcome happens. A 14¢ price means traders put the chance near 14%. Where two venues list the same outcome, we blend their last prices, weighting the venue with more trading volume more heavily (neither counts for less than a quarter). When only one outcome can win, each venue’s prices add up to a little over 100% (its margin); the fair chance removes that margin so the outcomes add up to exactly 100%.

How is the payout worked out?

A Yes contract pays $1 if it wins, so at the best ask a $100 stake buys 100 ÷ ask contracts. At 18¢ that is about 555 contracts, paying $556 (5.56x) if Yes happens. Venue fees and price slippage on larger orders are not included.

Why do the venues show different prices?

Each venue has its own traders, fees and order book. Contracts can also settle on slightly different terms, which is why each row lists how closely the rules match.

Is a price gap an arbitrage?

Only when you can buy Yes on one venue below what someone pays for Yes on the other, after fees, and both contracts settle the same way. We show the executable bid and ask so you can check.

How fresh are these prices?

Venue prices refresh every few minutes, and the order book and live quotes stream continuously. Each venue’s card shows when we last observed it.

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