DEV Community: Rizon

Settlement manipulation in 5-minute Bitcoin markets, and what rolling horizons change

Rizon — Tue, 03 Nov 2026 05:50:03 +0000

Short answer: Dai, Jia and Yu (2026) found Bitcoin spot orders spiking in the last seconds of Polymarket's 5-minute windows, then reversing. A push against a side priced at 90¢ or more overturned it 34.2% of the time, against 1.0% with no push, and 821 wallets gained $8.2 million in those windows, 93% of it from retail traders. A push pays because a fixed window settles every position on one print. On a rolling horizon, expiries are spread across time, so a 10-second push reaches only the fills from a 10-second stretch: with the same position and the same push, it's worth about 30× less. A fixed 2× also caps the return at +100¢ per $1. A rolling horizon doesn't stop a holder pushing at their own expiry, and the study's point about length still applies: the shorter the horizon, the less a push has to overcome.

A market that settles on a price you can trade has a weak point: anyone holding the contract can trade that price at the moment it counts. This article sets out what the research found on Polymarket's 5-minute Bitcoin market, works through why the attack paid, and shows which parts a rolling horizon contract removes and which it doesn't.

What the study found

Settlement Manipulation in Prediction Markets, by David Dai, Ruizhe Jia and Shihao Yu, covers Polymarket's 5-minute Bitcoin contract from its launch on Feb 12 to Apr 8, 2026. At the time, one Chainlink price settled each window: the contract paid $1 if the close was above the open. Chainlink's price tracks Binance to within a few basis points, so a large order on Binance in the last seconds could carry the settlement across the strike. The price then drifted back.

In this article, a "push" means that order. It has nothing to do with the push that refunds a tie in a horizon contract.

The authors took the top tenth of windows by last-10-second order flow, about 1,600 windows, and compared them with the rest:

Per window	Windows with a push	Other windows
Net Binance order flow in the last 10 s ($M)	1.7	0.068
PnL of the wallets identified as manipulators ($)	+5,096	+6
PnL of retail traders ($)	−4,715	−221
PnL of market makers ($)	−381	+215
Windows where retail lost overall (%)	65	48

And a push changed who won. This is how often the cheaper side won, by what the dearer side cost 10 seconds before the close:

Price of the dearer side (¢)	Cheaper side won, push against the dearer side (%)	Cheaper side won, no push (%)
50–60	65.4	41.4
60–70	68.3	29.1
70–80	54.3	17.7
80–90	54.4	8.7
90–100	34.2	1.0

The findings have limits. The authors identify pushes from order flow and manipulators from realised profits, so they don't observe intent, and they don't link any wallet to a spot order. As CoinDesk reported, they didn't prove that the same people held the contracts and placed the orders. They do rule out hedging: the flow arrives in a burst at the very end, and it still appears when the contract is nearly decided and there's almost nothing to hedge.

Their remedy is a longer horizon. In their model, a longer window gives the price more time to wander from the strike, so a push of a given size can change the result less often. The 15-minute contract, settled by the same oracle and heavily traded, supports it: the order-flow jump at its close was 0.068 log points against 0.406 for the 5-minute contract, with no reversal. They also list averaging or randomising the close, capping positions and taxing spot trades at settlement, and they call it "a settlement-design problem".

They didn't study rolling contracts. Both contracts in their data are fixed windows, and no real-money order book lists rolling ones, so there's nothing to measure yet. What follows is our arithmetic on their mechanism, not their finding.

Why a push pays

The gain from a push comes down to one line:

gain = position that settles on the push × how far the push moves its win chance − cost of the push

The cost is set by the spot market. The first two terms are set by the contract, and a fixed window priced in cents is generous on both. We tested them on 30 days of Bitcoin prices at 1-second resolution (Sep 27 to Oct 26, 2026, Binance BTCUSDT, 8,638 five-minute windows), with a push of 5 basis points, about $42 at that month's price of $83,800.

1. How much of a position one push reaches

This is the largest difference. In a fixed window, every position settles on the same print, however early it was built. A rolling contract has its own expiry, a fixed time after its own fill. Build the same position in both, evenly over 5 minutes, and push for the last 10 seconds of a fixed window or for any 10 seconds of a rolling book:

	Fixed 5-minute window	Rolling 5-minute contracts
Position built over 5 minutes	$3,000	$3,000
Share of it settling during a 10 s push	All of it	1/30 of it
Position settling during the push	$3,000	$100
Win chance without the push (%)	49.4	49.4
Win chance with a 5 bp push (%)	76.8	77.0
Expected gain from the push	$1,644	$55

The push moves the win chance by the same amount, but it reaches 30 times less of the position. To reach the rest, you'd have to hold the price up for 5 minutes rather than 10 seconds, and the study's pushes are bursts that start reversing within 10 seconds.

A trader can still aim for a slice by buying a lot in one burst. Only fills in the same second share an expiry on Rizon, so a position that settles within a 10-second push has to be filled within a 10-second stretch, one horizon earlier. That means taking whatever the book offers in those seconds, at a strike that gets worse with each level, rather than building patiently over the window. The study's wallets earned about $5,096 a window. At +54¢ per $1, that takes about $9,400 of size filled inside those few seconds.

2. What a win pays

In a market priced in cents, the side behind gets cheap as the close nears. Over our sample, 10 seconds before the close, it was worth:

Side behind by (bp)	Fair price with no push (¢)
1	19.8
2	14.1
3	7.9
5	1.5

Holding a contract at those prices when a push carries it pays many times over. Buying the side behind by up to 5 basis points, at those prices, and pushing 5 basis points returned +567¢ per $1 in our sample, with the win chance going from 14.3% to 95.3%. The study's most striking number sits at this end of the table: sides priced under 10¢ won a third of the time when pushed.

A horizon contract has no such price. Every contract costs half its payout, so a win returns +100¢ per $1 and no more, on any horizon and however far the number is from the strike.

Treat the +567¢ as a ceiling. It assumes you can buy at the fair price, and the study finds market makers pulling quotes near the close. We also can't tell what those wallets paid. And the 15-minute window offers the same cheap prices in our data, yet the study finds little there, so this can't be the whole story.

3. Buying after you've looked

A fixed window stays on sale until the close, at a strike set minutes ago. So a trader can watch the price, see that it's near the strike with seconds left, and only then buy. A rolling market has nothing like that on sale. Every fill starts a new contract with a full horizon ahead and a strike near spot, so whoever plans to push has to commit a full horizon before they can know whether the price will be anywhere near their strike.

What a rolling horizon doesn't change

A push still moves the win chance. A holder can still trade spot at their own expiry. A rolling 5-minute contract has the same spread of outcomes as a fixed 5-minute window bought at the open: +54¢ per $1 for a 5 bp push on both. What the rolling market removes is the reach, the cheap price and the look first, not the push.

Length matters as much as ever. The study's central result carries over: the shorter the horizon, the less the price wanders before expiry, and the more a push decides.

Rolling horizon	Win chance without the push (%)	Win chance with a 5 bp push (%)	Expected PnL per $1 of size with the push (¢)
5 minutes	49.4	77.0	+53.9
1 minute	47.3	91.6	+83.1
15 seconds	41.4	98.2	+96.4

(The win chances without a push fall short of 50% because of ties, which refund both sides.) Rizon's 15-second and 1-minute books are shorter than the contract in the study. A 5 bp push nearly decides a 15-second contract, so on those horizons the protection is the cap and the reach, not the difficulty of the push.

The settlement rule still matters. Rizon's rolling markets settle on the last live price at or before expiry: one print, from Coinbase, with Kraken as backup. That's fine for paper money, where there's nothing to gain. A real-money rolling market should settle on an average across venues.

It's untested. This is reasoning and arithmetic. Nobody has measured manipulation on a real-money rolling order book, and paper money gives nobody a reason to try.

What each fix does

These aren't rival fixes. Each removes a different part of the attack, and they'd be stronger together.

Fix	What it removes	Who uses it
A longer horizon	The share of windows where a push can change the result. Within 5 bp of the strike 10 s before the close: 54.3% of 5-minute windows, 37.8% of 15-minute	The study's main remedy
Averaging the close	Most of a short push's effect. A 5 bp push over the last 10 s moves a 60 s average by 0.83 bp, and only 11.8% of windows sit that close	Polymarket since August 2026, Kalshi since January 2026
A rolling expiry	The reach of one push: fills from seconds, not a whole window	Rizon
A fixed 2× price	The cheap side: a win returns +100¢ per $1 at most	Rizon
Position caps, randomised closes, a tax on settlement-window spot trades	The size of the prize, or the certainty of its timing	Proposed in the study

FAQ

What is settlement manipulation?

Holding a contract that settles on a price, then trading the underlying at settlement to move that price in your favour. The price usually drifts back afterwards, because the order carried no information.

Were Polymarket's 5-minute markets manipulated?

A 2026 study found the pattern you'd expect from manipulation: large Binance orders in the last 10 seconds, price reversals afterwards, and $8.2 million of gains to 821 wallets in those windows. It doesn't prove intent, or that the same people held the contracts and placed the orders.

Did Polymarket fix it?

It changed the rule. In August 2026 Polymarket moved its crypto up/down markets from a single price to a time-weighted average, which makes a short push much weaker. We haven't seen a published measurement of how much that reduced it.

Are rolling horizon contracts immune to manipulation?

No. A holder can still trade spot at their own expiry, and a short horizon makes that easier. A rolling market limits how much one push can reach, and a fixed 2× limits what a win pays: the same push on the same position is worth about 30× less over 5 minutes, but it isn't worth nothing.

Why was the 15-minute contract much less affected?

Because the price has more time to wander, it's less often near the strike at the close, so a push of a given size changes the result less often. That's the study's explanation, and our data shows the same thing: 37.8% of 15-minute windows are within 5 bp of the strike 10 seconds out, against 54.3% of 5-minute windows.

Can Rizon's markets be manipulated?

Rizon is paper money, so there's nothing to gain today. If it listed real money, its short horizons and its single-print settlement would need the fixes above.

Originally published at rizon.markets. Rizon is a paper-money exchange for horizon contracts.

How to price a horizon contract: the fair strike, your edge and what a quote costs

Rizon — Tue, 03 Nov 2026 05:45:08 +0000

Short answer: The price of a horizon contract is fixed: you pay your size and a win pays 2×. What you price is the strike, and the fair strike is the median of the number at expiry, the level it's as likely to finish above as below. Higher at a strike K is worth 2 × P(X > K) − 1 per $1 of size, and Lower is the negative of that. On a live price over a short horizon, the median is about spot and volatility gives you the win chance; on an event, you read the median from the bucket prices. At a 55% win chance, the expected profit is 10¢ per $1 of size, and the full Kelly fraction is 10%.

A horizon contract pays 2× if a number finishes on your side of a strike, and the order book quotes the strike. This guide is the math behind one: where fair is, what being off fair is worth, and what it costs to trade there.

The payoff in one line

With size s, strike K and the number X at expiry, ignoring pushes:

Side	Win chance	Expected PnL
Higher	p = P(X > K)	s × (2p − 1)
Lower	1 − p	s × (1 − 2p)

So the contract is fair exactly where p = 50%, which is the median of X. A strike below the median favours Higher and a strike above it favours Lower.

On a live feed: the win chance comes from volatility

Over a short horizon, drift is tiny against volatility, so the median of the price at expiry is about spot. If moves are roughly normal with standard deviation σ over the horizon and your fair value is m:

P(X > K) ≈ Φ((m − K) ÷ σ)

Real moves aren't normal, so it's better to measure. For every second from Sep 27 to Oct 26, 2026, we checked where Bitcoin was one minute later, and how often it finished above a strike set some distance from the starting price (full table):

Strike vs spot ($)	Higher wins (%)	Expected PnL per $1 of size (¢)
−25	83.3	+66.6
−10	68.5	+37.0
+10	30.8	−38.4
+25	16.3	−67.4

Over that month, the 70¢ and 30¢ points sat about $11 either side of spot, which gives a one-sigma move of about $21 a minute.

So a contract's value is very sensitive to where its strike sits against spot. A $10 difference in strike is worth about 37¢ per $1 of size on a one-minute contract. It's why buying at a strike that's already stale is so expensive, and why the books re-quote several times a second.

On an event: the median comes from the buckets

For an election or a rate, there's no feed. But event venues list the whole distribution as buckets, and any ladder of prices gives you the median. Here are Polymarket's Republican House seats on Oct 29, 2026 (midpoints), read as a distribution:

Republican seats	Mid (¢)	Probability, normalised (%)	Cumulative (%)
Under 190	33.5	32.73	32.73
190–194	13	12.70	45.43
195–199	14	13.68	59.11
200–204	13.5	13.19	72.30
205–209	14	13.68	85.98
210–214	3.7	3.62	89.59
215–219	5.95	5.81	95.41
220–224	3.25	3.18	98.58
225–229	1.2	1.17	99.76
230 or more	0.25	0.24	100.00

The steps:

Normalise. The midpoints add up to 102.35¢, so divide each by 1.0235.
Find the bucket holding 50%. Cumulative probability passes 50% inside 195–199.
Interpolate. Treat seats as continuous, with the bucket running from 194.5 to 199.5. The median is 194.5 + 5 × (50 − 45.43) ÷ 13.68 = 196.2 seats.

Kalshi's 11 buckets gave 196.1 that same day, a useful cross-check. Spreading each bucket's probability evenly is an assumption, and it only matters inside a bucket. On that distribution:

Strike (seats)	Higher wins (%)	Higher's expected PnL per $1 (¢)	Lower's expected PnL per $1 (¢)
194.5	54.57	+9.1	−9.1
195.5	51.83	+3.7	−3.7
196.5	49.10	−1.8	+1.8
197.5	46.36	−7.3	+7.3

So one seat of strike was worth about 5.5¢ per $1 of size in the middle of this market. A date market works the same way, with "by Nov 20" prices as the cumulative column, and the US–Iran post goes through one.

One complication: when a single value holds a lump of probability, the distribution has a jump and may have no strike at 50%. A Fed decision is the clearest case (the December 2026 meeting traded 76.5¢ for a hike). A book on it would have nowhere to trade near 50/50, which is why Rizon lists the rate at the end of 2027 instead, where the distribution is smooth.

The open-source bots implement all this in src/dist.ts: buckets, ladders and point masses all go into one piecewise-linear CDF, and the quotes come from its percentiles.

What an edge is worth

Say your forecast of the median is δ above the market's and the strike sits at the market's median. Your win chance on Higher is about 50% + f × δ, where f is the density at the strike. For a normal distribution, f = 0.399 ÷ σ, so:

Your edge on the median (σ)	Win chance (%)	Expected PnL per $1 of size (¢)	Sharpe per trade	Full Kelly fraction (%)
0.05	52.0	4.0	0.04	4.0
0.10	54.0	8.0	0.08	8.0
0.20	57.9	15.9	0.16	15.9
0.50	69.1	38.3	0.41	38.3

This is the argument for trading at the median: the density is highest there, so the same forecast edge is worth more than at any other strike. Why every market on Rizon is 50/50 has the comparison with contracts priced at other levels.

What a quote costs

There's no fee on Rizon, so the only cost is the spread: the distance from the midpoint to where you trade. If you buy, you take the best ask, a strike above the midpoint. What that distance costs depends on its size against σ, the horizon's one-sigma move. It's 1 − 2Φ(−h ÷ σ) per $1 of size, where h is the half-spread, or about 0.8 × h ÷ σ:

Half-spread ÷ σ	Win chance with no edge (%)	Cost per $1 of size (¢)
0.01	49.6	0.8
0.02	49.2	1.6
0.05	48.0	4.0
0.10	46.0	8.0

Every order book has this cost, and it moves with the spread. GET /markets publishes each book's bid, ask and sigma, so you can work it out at any moment.

The same measure works on a cents market. A book 1¢ wide at 50¢ leaves a taker a 49.5% win chance at the ask, a cost of 1¢ per $1 paid. Polymarket and Kalshi then charge takers about 1.75¢ a share at 50¢, about 3.5¢ per $1 paid, on top of that. Rizon charges no fee, so at the same spread it's cheaper by exactly that much.

Resting your own order on the book, rather than taking one, turns the spread in your favour, and the market-making guide covers that.

Sizing it

A horizon contract is an even payoff, so the Kelly fraction is simple: f = 2p − 1 of your bankroll. At 55% that's 10%, and at 52% it's 4%. Most traders use a fraction of Kelly, because your p is an estimate and full Kelly is punishing when it's wrong. Two more things are specific to this contract:

Overlapping rolling contracts aren't independent. Ten 5-minute positions opened a minute apart share most of their price path, so they add up to one larger position.
Your size is fully paid. Everything you commit is out of your balance until expiry, so capital is tied up for the horizon. On a fixed market, that can be a long time.

FAQ

What is the fair price of a horizon contract?

The price is fixed at 50/50: you pay your size, and a win pays 2×. What's fair or unfair is the strike, and the fair strike is the median of the number at expiry.

How do you calculate the expected value of a horizon contract?

Multiply your size by 2p − 1, where p is your chance of winning. At $100 and a 55% win chance, that's +$10. Pushes return your size, so they don't count for or against.

How does volatility affect a horizon contract?

It doesn't change the price, which is fixed. It changes what a given distance from the strike is worth: the higher the volatility, the closer to 50% a strike $10 from spot is. Volatility is why a longer horizon has a wider spread in dollars at about the same cost in win chance.

How do you convert an event contract's price into a horizon contract's strike?

If a contract paying above strike K trades at c cents and you have a σ for the number, the 50/50 strike is about K + σ × Φ⁻¹(c). With a whole ladder of prices, use the cumulative method above instead. Strike vs probability goes through the conversion with Bitcoin data.

Does a horizon contract have time decay?

It has no premium to decay, because the price is fixed and there's no selling it back. An open position's value still changes with time: as expiry nears, a contract in the money becomes more likely to win, and its hedged value moves closer to 2×.

Can I price a horizon contract with Black-Scholes?

For a price feed, the Black-Scholes value of a cash-or-nothing call is its discounted risk-neutral chance of finishing above the strike, N(d2), and setting that to 50% gives the fair strike. Over seconds to minutes, that's spot, near enough, and real short-horizon moves are too fat-tailed for the normal curve to give good numbers away from the median. For events, there's no underlying to hedge with, so you work from the distribution directly.

Originally published at rizon.markets. Rizon is a paper-money exchange for horizon contracts.

What is a horizon contract? Definition, payout and examples

Rizon — Tue, 03 Nov 2026 05:44:30 +0000

Short answer: A horizon contract is a binary contract on a number (a price, a seat count, a rate or a date) that always pays a fixed 2×: you take Higher or Lower, and you win if the number finishes on your side of the strike. Its order book quotes strikes instead of prices in cents, so the price never moves and every contract trades at 50/50, around the market's median. The horizon is rolling (each contract expires a fixed time after its own fill: 15 seconds to 5 minutes on Rizon's prices, and 1 to 30 whole UTC days on its uptimes) or fixed (every contract settles on one date or result); in a date market, the number is itself a date.

Rizon is an exchange for horizon contracts, traded with practice money. This guide defines the contract in plain English, the three kinds of horizon, and how it differs from the event contracts sold on Polymarket and Kalshi. The reference has the formal definition and the pricing, and the manifesto makes the case for why we think prediction markets will work this way.

The contract

Part	What it is
The number	Anything with a value at a known time: Bitcoin's price, Republican House seats, the Fed's upper bound, the day something happens
Strike	The level the number has to finish above (Higher) or below (Lower). The order book quotes it
Side	Higher wins above the strike, Lower below it
Payout	2× your size if you win, nothing if you lose
Horizon	When the contract expires: a fixed time after your fill (rolling), or one date for everyone (fixed)
Push	Both sides get their size back: when the number lands exactly on a strike (only where it can), or when the source has no value at expiry (Bitcoin and gold: no live price in the 5 seconds before)

An example: $100 on Higher than 196.5 on Rizon's Republican House seats market (HOUSE-R-2026) pays $200 if Republicans win 197 seats or more, and nothing if they win 196 or fewer. A seat count can't land on 196.5, so that contract can't push. Bitcoin's strikes are whole dollars, and the price can finish exactly on one; then both sides get their size back.

The most a contract can lose is your size, and the most it can make is your size again. It runs to expiry: a contract can't be sold back, only hedged with the other side.

The book quotes strikes, so every contract is 50/50

An event contract fixes the question ("Will Republicans win 195–199 seats?") and lets the price float between 0¢ and 100¢. A horizon contract fixes the price (2×, the same as buying a $1 contract at 50¢) and lets the strike float. The book works like a futures book whose price is the strike: Higher orders are bids, Lower orders are asks, and they meet where traders disagree about which side is ahead. That's the strike the market sees as 50/50, its median. The midpoint of the best bid and the best ask is the market's forecast of the number, in the number's own units: seats, percent, posts, a date.

Why fix the price there: a better forecast is worth the most at 50/50. What a forecast edge earns is roughly that edge times the density at the strike, and the density is highest in the middle of the distribution. Event venues price most of their markets far from the middle: of 173 prices we recorded on Oct 29, 2026 on Polymarket and Kalshi markets on Rizon's questions (and the Fed's December decision), 98 were under 10¢ or over 90¢ and 5 were between 40¢ and 60¢. The arithmetic is in Why every market on Rizon is 50/50, and how strikes and cents convert is in Strike vs probability.

Three kinds of horizon

Rolling. Each contract expires a fixed time after its own fill, on the first whole second at least that far on: a fill at 15:24:41.3 on a 1-minute market expires at 15:25:42. Every trader gets the full horizon, whenever they arrive, and fills in the same second share one expiry. Rolling fits numbers with a live feed: Bitcoin and gold over 15 seconds, 1 minute or 5 minutes; claude.ai's and Polymarket's uptime over the next 1, 7 or 30 days, on whole UTC days.

Fixed. Every contract expires at one moment, and trading stops at a set close or when the result is known (Rizon halts the House market once every race is called). A fixed market settles on its result from a named source, not on a timer (Rizon resolves most by hand from that source; the Fed and the 10-year yield resolve automatically), and a result that comes in early settles every open contract at once. Two are void, with everyone refunded, if their event never happens: Anthropic's first-day market cap if it hasn't listed by the end of 2027, and predict.fun's FDV if there's no token by then.

Date. A market whose number is a date: the day something happens, written as a Julian Day Number (JDN), the day count astronomers use (Oct 29, 2026 is JDN 2,461,343). Strikes sit on the halves between day numbers, which are the midnights between days, so "Higher than Nov 15" means Nov 15 or later and Lower means Nov 14 or earlier, and a date market never pushes. A contract expires at its strike's midnight or the market's deadline, whichever comes first, plus 2 days for the source to report. If the event hasn't happened by the deadline, Higher wins. The US–Iran post works through one.

Kind	Expires	Settles on	Can it push?
Rolling	Fill time plus the horizon, on the next whole second (an uptime: the next UTC midnight)	The feed's value at expiry	Yes, where the value can equal a strike (Bitcoin, gold)
Fixed	One moment for every contract	The result, from the named source	Not on seats, counts, rates or yields: strikes sit between values
Date	The strike's midnight or the deadline, plus 2 days	The day the event happens	No

More on choosing between them in Fixed vs rolling horizons.

What's listed

The market list as of Oct 30, 2026 (the markets panel in the app is the live list):

Category	Market	Id	Horizon
Crypto	Bitcoin	BTC-15s, BTC-1m, BTC-5m	Rolling: 15 s, 1 m, 5 m
Crypto	predict.fun FDV, a day after launch	PREDICT-FDV	Fixed
Commodities	Gold (PAXG)	GOLD-15s, GOLD-1m, GOLD-5m	Rolling: 15 s, 1 m, 5 m
Politics	House seats: Republicans	HOUSE-R-2026	Fixed
Politics	Senate seats: Republicans	SENATE-R-2026	Fixed
Politics	House popular vote margin	HOUSE-VOTE-2026	Fixed
Politics	US–Iran ceasefire: the next US strike	IRAN-STRIKE	Date
Economy	Fed rate, end of 2027	FED-2027	Fixed
Economy	10-year yield, highest close by Dec 31	UST10Y-MAX-2026	Fixed
Tech	Anthropic IPO: date	ANTH-IPO-DATE	Date
Tech	Anthropic IPO: first-day market cap	ANTH-IPO-CAP	Fixed
Tech	Next Fable model	FABLE-NEXT	Date
Culture	Elon's posts, 2026	ELON-1d, ELON-7d	Rolling: 1 d, 7 d
Uptime	claude.ai uptime	CLAUDE-UP-1d, CLAUDE-UP-7d, CLAUDE-UP-30d	Rolling: 1, 7, 30 days (on UTC midnights)
Uptime	Polymarket uptime	POLY-UP-1d, POLY-UP-7d, POLY-UP-30d	Rolling: 1, 7, 30 days (on UTC midnights)

Horizon contract vs event contract

	Event contract (Polymarket, Kalshi)	Horizon contract (Rizon)
What you buy	Yes or No on one bucket, date or strike	Higher or Lower on the number
Price	Floats from 0¢ to 100¢	Fixed: pays 2×, like 50¢ for $1
What moves	The price	The strike
One number becomes	Many markets: 10 for House seats on Polymarket, about 30 for Elon Musk's weekly posts	One book
Where prices sit (Oct 29, 2026)	98 of 173 under 10¢ or over 90¢	50/50 by construction
What a win pays	$1 a share	2× your size
The forecast	Add up the buckets	The book's midpoint
Time	Blocks on the clock for crypto; one date for events	From your fill, or one date for events

FAQ

What is a horizon contract in simple terms?

A contract that pays 2× your size if a number finishes on your side of a strike, Higher or Lower. The market moves the strike rather than the price, so every contract is priced at 50/50.

Why is it called a horizon contract?

Because it's defined by its horizon, how far ahead the number is measured: a fixed time from your own trade (15 seconds to 30 days on Rizon) or a date everyone shares. The name Rizon comes from "horizon" too.

Is a horizon contract a binary option?

By payoff, yes: a fixed amount or nothing at expiry. The market around it is different: the price is fixed, an order book sets the strike, and the other side is another trader. See horizon contract vs binary option.

What's the difference between a horizon contract and an event contract?

An event contract fixes the question and lets the price float from 0¢ to 100¢. A horizon contract fixes the price and lets the strike float. See horizon contract vs event contract.

Is a horizon contract the same as an up/down market?

They're related. An up/down market fixes the strike at the opening price of a window on the clock and lets the price in cents drift; a horizon contract fixes the price at 2× and lets the book set the strike, from your fill or for an event date.

What is a Julian Day Number?

A whole-number count of days that astronomers use: Oct 29, 2026 is 2,461,343. Rizon's date markets quote dates this way, with strikes on the halves between them, which are the midnights.

Is this related to Horizon Trading Solutions or Horizon Protocol?

No. Those are companies with Horizon in their names. A horizon contract is a type of contract, named for how far ahead its number is measured.

Is Rizon real money?

No. Rizon is a paper exchange: practice money, no deposits. The other venues' prices quoted here are Polymarket's and Kalshi's, recorded on Oct 29, 2026.

Originally published at rizon.markets. Rizon is a paper-money exchange for horizon contracts.