The Prediction Markets

NYC population change in Mamdani's first 18 months?

Closes
Jun 1, 2028, in 20 months
Traded
$89K
Venues
Kalshi
Prices updated
2 min ago
Share

What the markets expect

Increase 0.01-0.99% 38.6%

Next is No change or decrease 0–0.99% at 32.3%. Only Kalshi lists this market, so there is no second price to compare.

Increase 0.01-0.99% 38.6%No change or decrease 0–0.99% 32.3%Decrease 1-1.99% 9.4%Increase 1-1.99% 7.3%Increase 3% or more 5.2%3 others 7.2%

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 2 min ago. Ages are as of when this page was built.

  • Kalshi
Increase 0.01-0.99%
38.6%
Kalshi 37%(38.5% fair)polled, 2 min agoBest Yes 45¢ on Kalshi, $100 pays $222 (2.22x)
Kalshi
Contract
Increase 0.01-0.99%
Last price
37%
Fair, margin removed
38.5%
As of
Polled 2 min ago
Buy Yes
45¢
Sell Yes
37¢
$100 on Yes pays
$222 (2.22x)
Volume
$15K
Trade this on Kalshi
No change or decrease 0–0.99%
32.3%
Kalshi 31%(32.3% fair)polled, 2 min agoBest Yes 32¢ on Kalshi, $100 pays $313 (3.13x)
Kalshi
Contract
No change or decrease 0–0.99%
Last price
31%
Fair, margin removed
32.3%
As of
Polled 2 min ago
Buy Yes
32¢
Sell Yes
30¢
$100 on Yes pays
$313 (3.13x)
Volume
$23K
Trade this on Kalshi
Decrease 1-1.99%
9.4%
Kalshi 9%polled, 2 min agoBest Yes 11¢ on Kalshi, $100 pays $909 (9.09x)
Kalshi
Contract
Decrease 1-1.99%
Last price
9%
As of
Polled 2 min ago
Buy Yes
11¢
Sell Yes
2¢
$100 on Yes pays
$909 (9.09x)
Volume
$10K
Trade this on Kalshi
Increase 1-1.99%
7.3%
Kalshi 7%polled, 2 min agoBest Yes 7¢ on Kalshi, $100 pays $1,429 (14.3x)
Kalshi
Contract
Increase 1-1.99%
Last price
7%
As of
Polled 2 min ago
Buy Yes
7¢
Sell Yes
3¢
$100 on Yes pays
$1,429 (14.3x)
Volume
$11K
Trade this on Kalshi
Increase 3% or more
5.2%
Kalshi 5%polled, 2 min agoBest Yes 7¢ on Kalshi, $100 pays $1,429 (14.3x)
Kalshi
Contract
Increase 3% or more
Last price
5%
As of
Polled 2 min ago
Buy Yes
7¢
Sell Yes
1¢
$100 on Yes pays
$1,429 (14.3x)
Volume
$10K
Trade this on Kalshi
Decrease 2-2.99%
3.1%
Kalshi 3%polled, 2 min agoBest Yes 3¢ on Kalshi, $100 pays $3,333 (33.3x)
Kalshi
Contract
Decrease 2-2.99%
Last price
3%
As of
Polled 2 min ago
Buy Yes
3¢
Sell Yes
—
$100 on Yes pays
$3,333 (33.3x)
Volume
$4K
Trade this on Kalshi
Increase 2-2.99%
3.1%
Kalshi 3%polled, 2 min agoBest Yes 3¢ on Kalshi, $100 pays $3,333 (33.3x)
Kalshi
Contract
Increase 2-2.99%
Last price
3%
As of
Polled 2 min ago
Buy Yes
3¢
Sell Yes
—
$100 on Yes pays
$3,333 (33.3x)
Volume
$6K
Trade this on Kalshi
Decrease 3% or more
1%
Kalshi 1%polled, 2 min agoBest Yes 6¢ on Kalshi, $100 pays $1,667 (16.7x)
Kalshi
Contract
Decrease 3% or more
Last price
1%
As of
Polled 2 min ago
Buy Yes
6¢
Sell Yes
1¢
$100 on Yes pays
$1,667 (16.7x)
Volume
$9K
Trade this on Kalshi

Who resolves this market

Kalshi
Kalshi resolves via:
Kalshi (CFTC-regulated exchange), source: United States Census Bureau

How the odds have moved

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

  • Increase 0.01-0.99%
  • No change or decrease 0–0.99%
  • Decrease 1-1.99%

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.

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

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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 0.04 × price × (1 − price) per share (politics rate). Fee calculator. Estimates only, not advice.

About this market

Live prediction market odds for "NYC population change in Mamdani's first 18 months?". Increase 0.01-0.99% leads at 38.6%. Next is No change or decrease 0–0.99% at 32.3%. $89K has traded across 8 outcomes on Kalshi. The market is expected to resolve by Jun 1, 2028.

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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