DEV Community: John Leslie

Are Prediction Markets Well-Calibrated? I Analyzed 7,661 Resolved Polymarket Markets

John Leslie — Sat, 25 Apr 2026 15:33:05 +0000

By John Leslie

Prediction markets are booming. Polymarket alone processes billions in volume. But a fundamental question remains: when a market says there's a 60% chance of something happening, does that event actually happen 60% of the time?

I pulled 7,661 resolved binary markets from Polymarket's API, grabbed price history for the top 2,000 by volume, and built an interactive calibration tracker to find out.

Try it here: Polymarket Calibration Tracker

What is calibration?

A forecaster is well-calibrated if their predicted probabilities match observed frequencies. If you say "70% chance" for 100 different events, roughly 70 of them should happen. Perfect calibration means every point sits on the diagonal line where predicted = actual.

This is the gold standard metric for forecast quality, used everywhere from weather forecasting (the NWS publishes calibration curves) to machine learning model evaluation.

The results

Markets are excellent at the extremes

Events priced at 0-5% almost never happen (0.1% actual resolution rate). Events at 95-100% always happen (100% actual). This is reassuring: when the crowd is very confident, the crowd is right.

Systematic underpricing in the middle range

This is where it gets interesting. Markets trading at 65-75% actually resolved YES 96.5% of the time (29 markets). At 45-55%, the actual rate was 60% (25 markets). The sample sizes are small in these middle bins, so interpret cautiously, but the pattern is consistent: mid-range markets seem to underprice the YES outcome.

One hypothesis: multi-outcome markets inflate the low-probability bins. If there are 10 candidates in an election, 9 of them trade at 0-5% and lose, pulling the average down. The winners cluster higher. This creates a distributional skew that looks like underpricing in the middle.

Calibration improves closer to resolution

This makes intuitive sense. The 24-hour Brier score (0.025) is significantly better than the 30-day score (0.042). As resolution approaches, uncertainty resolves, and prices converge to 0 or 1.

For context: random guessing on balanced outcomes gives a Brier score of 0.25. A Brier score of 0.025 is excellent.

Category breakdown

The tool lets you filter by category. Some highlights:

Politics (1,312 markets): Well-calibrated at extremes, biggest mid-range deviation
Sports (1,314 markets): Similar pattern to politics, slightly tighter calibration
Crypto (752 markets): More volatile, noisier calibration curve
Geopolitics (404 markets): Small sample but interesting patterns
Science/Tech (163 markets): Too few markets for reliable conclusions

Technical details

Data collection: Polymarket's Gamma API for resolved market metadata. CLOB (Central Limit Order Book) midpoint prices at 24h, 7d, and 30d before resolution for the top 2,000 markets by volume.

Methodology: Markets binned into probability ranges (0-5%, 5-15%, ..., 95-100%). For each bin, the actual resolution rate is compared to the predicted probability. Proportional dot sizes indicate sample count.

Caveats:

75% of price-tracked markets fall in the 0-5% bin, driven by multi-outcome market losers
Small sample sizes in mid-range bins (20-50 markets each) limit statistical significance
Only resolved markets are included (survivorship consideration)

Why this matters

Prediction markets are being used for increasingly high-stakes decisions. DARPA studied them for intelligence forecasting. The Federal Reserve has explored them for inflation expectations. Companies like Google and HP have used internal prediction markets for product planning.

If these markets are well-calibrated, their prices can be treated as genuine probability estimates. If they're systematically biased, traders and decision-makers need to adjust.

The data suggests Polymarket is well-calibrated overall (Brier score 0.025), with some interesting biases in the middle range worth investigating further as sample sizes grow.

Explore the data yourself: polymarket-calibration.vercel.app

I write The Market Oracle, a weekly prediction market intelligence newsletter. Read more at our site.

The Regulatory Storm: 7 Bills, 3 Bans, and the Future of Prediction Markets

John Leslie — Sat, 25 Apr 2026 07:46:46 +0000

Originally published at The Market Oracle

Prediction markets just became Washington's hottest regulatory target. In a single week: seven congressional bills introduced targeting prediction market oversight, three state-level enforcement actions, Kalshi's first-ever self-enforcement against politicians betting on their own races, and the DOJ's first insider trading prosecution in the space.

The Regulatory Blitz

Seven bills. One week. That's not a regulatory drip -- that's a flood.

The headline legislation is the bipartisan PREDICT Act, which would ban politicians and their immediate family members from trading on political events.

New York Governor Hochul issued an executive order banning all state employees from prediction market insider trading. Connecticut, Arizona, and Illinois attempted outright bans. The federal government simultaneously sued all three states to block their actions -- arguing prediction markets fall under CFTC jurisdiction.

Our take: Regulation is coming, but it's bullish long-term. Clear rules mean institutional adoption.

Kalshi Becomes the Sheriff

Kalshi fined and suspended three congressional candidates for placing wagers on their own races -- the first enforcement action of its kind. Fines ranged from \$539 to \$6,229.

The fines are small. The signal is enormous. Self-policing is the cheapest insurance against existential regulatory risk.

Hormuz: The Dual Blockade Tightens

Five ships transited in the last 24 hours. The pre-crisis average was 140 per day. Oil at \$105/barrel.

April normalization at 1.7% -- effectively resolved NO, exactly as we called when it was at 38%. Our portfolio: +61.2%.

Portfolio: +61.2%

Position	Entry	Current	P&L
Hormuz April NO	YES 38%	YES 1.7%	+58.6%
Hormuz May NO	YES 69.5%	YES 37%	+106.4%
Total	\$1,000	\$1,612	+61.2%

Read the full issue | All issues

When Prediction Markets Become the News: Shoot-and-Kill Orders, Fox News Deals, and John Oliver

John Leslie — Fri, 24 Apr 2026 11:18:25 +0000

Trump just ordered the Navy to shoot Iranian mining boats in the Hormuz Strait. Kalshi is now embedded in Fox News, CNN, and CNBC. John Oliver devoted a segment to prediction markets. Forbes created a market on a children's mass shooting. And our fictional portfolio just crossed +63.6% in 4 days.

This week, prediction markets stopped being a niche curiosity and became the news itself.

"Shoot and Kill"

On April 23, President Trump ordered the US Navy to "shoot and kill" any boats caught laying sea mines in the Strait of Hormuz. The order came after Iran seized two more ships and fired RPGs at a Greek-owned cargo vessel.

The Strait remains effectively closed. The US naval blockade has turned back 31 Iran-linked vessels since April 13. Iran says reopening is impossible while the blockade continues. Oil is at $95/barrel.

Portfolio impact: When we opened our May NO position on April 20, YES was at 69.5%. It's now at 33.5%. Our position is up 117.9% on that leg alone. The "shoot and kill" order is not the language of de-escalation. We're revising our May fair value estimate down to 15-20%. The position stays open.

Prediction Markets Go Primetime

Kalshi has signed partnerships with CNBC, CNN, Fox News, and the AP. Fox Corporation announced it will weave real-time prediction data into Fox News, Fox Business, Fox Weather, and streaming. When you watch cable news, you now see prediction market odds alongside stock tickers.

Kate Knibbs at Wired established herself as a dedicated prediction markets reporter. Polymarket partnered with Substack (Feb) and Dow Jones (Jan). The infrastructure of mainstream coverage is being built in real time.

John Oliver devoted a Last Week Tonight segment to prediction markets, questioning the industry's rapid expansion and regulatory gaps. When a comedian covers your industry, you've gone mainstream.

Where's the Line?

Not everyone is celebrating.

Forbes created a prediction market that gamified a mass shooting that killed eight children. The backlash was immediate (reported by 404 Media, April 20). The dark side of "a prediction market for everything": some events should not be betting opportunities.

ProPublica added a section to its ethics code prohibiting staff from betting on news events through prediction markets. The concern: when journalists can bet on outcomes they cover, the language of forecasting begins to influence the language of reporting.

The Columbia Journalism Review published a deep analysis warning that the CFTC's pro-prediction-market posture may not survive a genuine crisis of public trust.

Portfolio: +63.6% in Four Days

Position	Entry	Current	P&L
Hormuz April NO	YES 38%	YES 2.9%	+56.5%
Hormuz May NO	YES 69.5%	YES 33.5%	+117.9%
Cash reserve	$200	$200	--
Total	$1,000	$1,636	+63.6%

We called April at 38% -- it's now 2.9%. We called May overpriced at 69.5% -- it's now 33.5%. Both calls directionally correct. The "shoot and kill" order strengthens our conviction.

Market Snapshot

Hormuz May normalization: 33.5% YES (was 69.5% four days ago)
Hormuz June normalization: 57.5% YES
2028 Presidential: JD Vance 18.4%, Gavin Newsom 17.1%, Marco Rubio 10.2%
Democrats win House 2026: 84.5% YES
Eurovision 2026: Finland 36.4%

Read the full analysis with more detail at The Market Oracle. Published by John Leslie.

The Soldier Who Bet on a Secret War: First DOJ Prediction Market Prosecution

John Leslie — Fri, 24 Apr 2026 07:47:13 +0000

A US Special Forces soldier used classified intelligence about a covert military operation to make $410,000 on Polymarket. The DOJ just filed the first-ever insider trading prosecution in prediction market history.

The Big Story: A Soldier Bet on a Secret War

On April 23, the Department of Justice charged Master Sergeant Gannon Ken Van Dyke, a US Special Forces soldier stationed at Fort Bragg, with using classified military intelligence to profit on Polymarket.

What he knew: Van Dyke participated in planning "Operation Absolute Resolve," the covert US operation to capture Venezuelan president Nicolas Maduro. He had advance knowledge of the timing and details of the raid.

What he did: He placed 13 bets totaling $33,000 on Polymarket markets tied to Maduro's capture and removal from power. When the operation succeeded, he collected $410,000 in profit. A 1,142% return on classified intelligence.

The charges: Three counts of violating the Commodity Exchange Act (up to 10 years each), wire fraud (up to 20 years), and unlawful monetary transaction (up to 10 years). First-ever DOJ prosecution for prediction market insider trading.

The Integrity Week

Kalshi suspended three congressional candidates for betting on their own races
Illinois Governor barred state employees from using insider info on prediction platforms
The White House warned staff against placing prediction market bets
A Harvard/Columbia paper identified $143 million in suspicious Polymarket profits

Prediction Markets Become Derivatives Exchanges

Polymarket launched perpetual futures (10x leverage) on April 21. Kalshi launching crypto perps April 27. Both competing with Coinbase and Robinhood now.

Kalshi leads in volume ($37.5B YTD vs Polymarket $29.2B) and valuation ($22B vs $15B target).

Hormuz Portfolio: +61.7%

Metric	Value
Starting capital	$1,000
Current value	$1,617
Return	+61.7%
Days held	4

May Hormuz dropped from 69.5% to 35.5%. April at 2.9%, effectively resolved.

The Market Oracle - weekly prediction market intelligence. Read more

Kalshi at $22B, Polymarket Raises $400M, and Our Portfolio Is Up 33.6%

John Leslie — Fri, 24 Apr 2026 07:37:01 +0000

Issue #2 · April 22, 2026 · By John Leslie

This week: Kalshi is valued at $22 billion and heading to the Supreme Court. Polymarket is raising $400M with the NYSE parent company backing it. Meanwhile, IRGC gunboats are seizing ships in the Strait of Hormuz and our fictional portfolio is up 33.6% in two days. The money is flooding in and the stakes keep rising.

The Big Story: The $37 Billion Week

Three developments this week prove prediction markets have crossed from crypto curiosity to financial infrastructure:

1. Kalshi raised $1B+ at a $22 billion valuation

Coatue Management led the round. Kalshi controls 89% of the regulated U.S. market (Bank of America, April 9). At $22B, Kalshi is now valued higher than the Chicago Board Options Exchange was at its 2005 IPO. This is not a bet on prediction markets. It is a bet that event contracts become a permanent asset class.

2. Polymarket is raising $400M at $15 billion

Intercontinental Exchange (ICE), the parent company of the New York Stock Exchange, has committed up to $2 billion. When the NYSE parent company writes a $2B check into prediction markets, the institutional legitimacy question is settled. The remaining question is who wins: regulated (Kalshi at $22B) or crypto-native (Polymarket at $15B)?

3. The Supreme Court is next

Kalshi's fight with states over whether prediction markets are derivatives or gambling is heading toward the Supreme Court. The outcome determines whether the industry operates under one federal framework (CFTC) or 50 state gaming commissions. Sports betting is currently 85% of volume for both major platforms. If the Court rules prediction markets are gambling, those contracts vanish overnight. If it rules they are derivatives, the CFTC becomes the sole regulator and institutional capital pours in.

What this means: The prediction market industry is expected to hit $200B in volume this year. Bernstein projects $1 trillion by 2030. The infrastructure war between Kalshi and Polymarket will define market structure for the next decade. For traders: enjoy the promotional pricing and tight spreads. This is two platforms spending billions to buy your order flow.

The Markets

Hormuz: IRGC Seizes Two More Vessels

Our call from Issue 1: April normalization at 38% was overpriced (fair value 5-10%), May at 69% was overpriced (fair value 40-50%).

Current prices: April 9% YES, May 59% YES. Both moved sharply in our direction.

The week timeline:

April 17: Iran declares the strait completely open. Oil drops 10%. Markets surge.

April 18: Iran reverses course. IRGC gunboats fire on two Indian-flagged ships. India summons the Iranian ambassador. Iran claims communication gap.

April 19: US Navy seizes Iranian cargo ship Touska after 6-hour standoff. Marines rappel from helicopters. Tehran vows retaliation. Iran parliament drafts a law requiring hostile country ships to get approval and pay tolls.

April 20: Zero tankers cross the strait. One of the quietest days since the crisis began.

April 21: Trump says he will not extend ceasefire. Warns of lots of bombs. US forces board oil tanker M/T Tifani in the Indian Ocean.

April 22 AM: Trump reverses, announces open-ended ceasefire extension, but the blockade stays fully in place. Iran FM Araghchi calls the blockade an act of war and a violation of the ceasefire.

April 22 PM: IRGC seizes two more vessels in the Strait of Hormuz. Negotiations deadlocked. About 800 vessels queued in the Gulf.

Updated call: April is effectively resolved as NO. May at 59% is still overpriced. Revised estimate: 30-40%. The blockade is becoming structural, not tactical. Iran is institutionalizing it with transit fees. The negotiating gap is massive (US wants 20-year enrichment pause, Iran offered 5 years). 3-8 ships per day are transiting vs. 60 needed. This does not unwind in 5 weeks.

Iran Regime Change: The Cheap Hedge

Will the Iranian regime fall by April 30 has $32M in volume despite trading at just 2% YES. Why does a 2% market have $32M?

Traders are using it as a cheap hedge. At 2 cents per share, a YES position is a lottery ticket. If Mojtaba Khamenei (installed as Supreme Leader on March 8 after his father's assassination) faces a coup, that 2-cent share becomes worth $1.

The longer-dated markets:

By May 31: 3%
By June 30: 7.5%
By end of 2026: 20%

The market says there is a 1-in-5 chance of regime change within 9 months.

2028 Presidential: Democrats Still Elevated

$548M in volume. Current top candidates:

JD Vance: 18.8%
Gavin Newsom: 17.8%
Marco Rubio: 10.2%
Alexandria Ocasio-Cortez: 5.9%
Kamala Harris: 4.1%

Democrats remain elevated, driven by backlash to Iran. Historical base rates suggest regression toward 50/50 this far from an election. I would not trade this either direction until the Hormuz situation resolves.

Eurovision: Finland Still Leads

Finland leads the overall winner market at 36%. Finland is the consensus pick but is not dominant in either the jury (13%) or televote (17%) sub-markets. Israel leads the televote at 38%. At 36%, Finland is probably fairly priced. The value, if any, is in Israel for the televote.

The Feature: Prediction Markets vs. The National Weather Service

The most underrated story in prediction markets right now.

ForecastEx has been offering daily high-temperature markets via Interactive Brokers ForecastTrader since November 2025. Patrick Brown, head of climate analytics at Interactive Brokers, found that prediction markets were more accurate than the National Weather Service.

Why would traders beat meteorologists with billion-dollar supercomputers?

They are not beating them. They are aggregating them. A prediction market on tomorrow's high temperature in Chicago does not replace the weather models. It combines them. Traders who follow the European model, the GFS model, local radar, and even look out the window all contribute to the price. The result is an ensemble of all available information, weighted by confidence.

This is the prediction market thesis in its purest form: markets as information aggregators. Not better than any individual expert, but better at combining all available expertise.

If markets can improve weather forecasting, they can improve forecasting of economic indicators, disease outbreaks, and supply chain disruptions. The category is about to get much bigger.

The Regulatory Corner

Federal wins:

CFTC enforcement advisory issued, signaling intent to regulate rather than kill the space
Third Circuit ruled prediction markets cannot be regulated by state gambling laws
New Jersey lost its appeal against Kalshi on sports contracts

State pushback:

Nevada issued a temporary ban on Kalshi
Arizona accused the platform of unlicensed gambling
Massachusetts secured preliminary injunction
40+ lawmakers led by Sen. Warren pushing for insider trading rules

The insider trading problem:

A trader made $400K correctly predicting the Maduro ouster in January
Another made about $300K on Biden pardon timing
A political candidate was caught trading on his own candidacy (fined $2,246, 5-year ban from Kalshi)

My read: federal primacy wins. The CFTC is suing states, which means they want jurisdiction. Kalshi regulatory moat deepens with each court victory. Long-term bullish for the industry. Short-term, expect volatility around rulings.

Track Record

Market	Issue	Call	Entry	Current	Status
Hormuz April	1	NO at 38%	38%	9%	Virtually resolved. +46.7%
Hormuz May	1	NO at 69%	69%	59%	Tracking right. +34.3%

Fictional $1,000 portfolio (started April 20): now worth $1,336 (+33.6% in 2 days). Two calls, both correct direction.

This is The Market Oracle, a weekly prediction market intelligence newsletter. Read more at https://site-two-nu-51.vercel.app

The Hair Dryer That Won $34,000: This Week in Prediction Markets

John Leslie — Fri, 24 Apr 2026 07:28:09 +0000

Issue #3 · April 23, 2026 · By John Leslie

Prediction markets just had their biggest integrity week ever. Kalshi suspended three congressional candidates for betting on their own races. Someone in Paris used a hair dryer to manipulate a Polymarket weather contract for $34,000. And in the Strait of Hormuz, our fictional portfolio just crossed +53.5% in three days. This issue: what these scandals mean for the industry, why they're actually bullish, and the markets that matter this week.

The Big Story: Politicians Caught Betting on Themselves

Kalshi dropped a bombshell on Tuesday: three congressional candidates were suspended for placing bets on their own political outcomes. This is the first time a U.S. prediction market has enforced "insider trading" rules against politicians.

The three cases:

Matthew Klein (D-MN), a state senator running for an open U.S. House seat, bet $50 that he'd win his own nomination back in October. He cooperated with Kalshi's investigation and was fined $530 plus a five-year ban.

Mark Moran (I-VA), running for U.S. Senate, bet that he would announce a political run, then publicly launched his campaign in January. He refused to cooperate and was fined $6,200 plus a five-year ban.

A Texas Republican who finished with 1% in a March primary bet on their own House race. Fined $780, five-year ban.

Why this matters: The bets were tiny ($50-$200 range). The penalties were modest. But the signal is enormous: Kalshi is building an enforcement infrastructure before regulators force one on them. Every prediction market exchange is watching. Polymarket has no comparable system.

The bigger picture: Congress has been scrutinizing prediction markets since the 2024 election. Multiple lawmakers have called for stricter regulation. By policing itself now, Kalshi is attempting to preempt regulation by demonstrating the industry can self-govern. Whether regulators buy that argument will shape the next decade of prediction markets.

What this means: This is exactly the kind of industry maturation that happens before mainstream adoption. Credit card companies went through it. Crypto exchanges went through it. The fact that prediction markets are having their "insider trading" moment means they're being taken seriously enough to need rules. Long-term, this is bullish for the industry.

The Hair Dryer That Won $34,000

This is the wildest prediction market story of the year.

Polymarket runs temperature contracts on Paris weather, settled using an automated sensor at Charles de Gaulle Airport. On April 6, someone walked up to the sensor and apparently aimed a hair dryer at it.

The result: The sensor recorded a 4C spike in 12 minutes, briefly hitting 22.5C before returning to normal. Neighboring stations showed nothing unusual. Polymarket paid out $14,000 on temperature contracts that resolved because of the spike.

It happened again. On April 15, the same sensor recorded another anomalous rise to 22C under calm, cloudy conditions. Another $20,000 in payouts.

Total haul: ~$34,000. Meteo France has filed criminal charges. Polymarket has since switched its Paris temperature source from CDG to the Paris-Le Bourget station.

Why this matters for bettors: Physical oracle manipulation is the prediction market equivalent of match-fixing. If a contract settles based on a single data point, someone will eventually try to manipulate that data point. Weather contracts are uniquely vulnerable because the sensors are physically accessible and automated. Before placing large positions: always check the resolution source. Multi-station averaging or satellite data would eliminate this attack vector, but neither platform has announced plans to switch.

Hormuz Tracker: Our Best Week Yet

Our flagship call continues to pay off. The fictional portfolio crossed +53.5% in three days.

Current prices (April 23, 09:20 CEST):

April normalization: 4.5% YES (down from 38% when we first called it). Effectively resolved as NO.
May normalization: 42.5% YES (down from 69.5% at our entry). Crashed 16.5 percentage points overnight.
June normalization: 66.5% YES (down from 88.5% at our first mention).

What happened this week: Trump extended the ceasefire indefinitely but the blockade stays. The IRGC seized two more container ships in the strait on April 22, hours after the ceasefire extension. Iran is institutionalizing control of the waterway, charging tolls exceeding $1 million per ship and seizing vessels that attempt unauthorized passage.

Updated call: May at 42.5% is now much closer to fair value. The structural thesis: the IRGC has transformed the blockade from a wartime tactic into an ongoing revenue and leverage operation. Reopening the strait requires either (a) a comprehensive deal that gives Iran something it values more than strait control, or (b) military action to clear IRGC naval assets. Neither appears imminent. Revised estimate for May: 25-35%.

Portfolio Update

Metric	Value
Starting capital (Apr 20)	$1,000
Current value	$1,535
Return	+53.5%
Best position	May NO: +88.4%
Days held	3

Markets Worth Watching

AI Model Race: Anthropic 94%, OpenAI 6%

Monthly Polymarket contract on best AI model. Claude Opus 4.7 launched April 16 and topped the Artificial Analysis index. At 94%, this feels like it could only surprise to the downside. OpenAI hasn't shipped a frontier model update in months. The 6% is priced as a long-shot lottery ticket, and honestly that's about right.

FIFA World Cup: $668M in Volume

The largest sports prediction market ever on Polymarket. Tournament starts June 11. Spain (16%), France (15.8%), England (10.9%). Wide open. No team has repeated since Brazil in 1962.

Supreme Court Watch

Circuit split forming between the Third Circuit (pro-Kalshi) and a pending Ninth Circuit case (potentially anti-Kalshi). If the Ninth Circuit rules against prediction markets, Supreme Court review becomes almost certain by 2027. This is the long-term regulatory risk that could reshape the entire industry.

Track Record

Call	Issue	Direction	Entry	Current	Move	Status
Hormuz Apr is a NO	#1	NO at 38%	62c	95.5c	+33.5c	Effectively won
Hormuz May overpriced	#1	NO at 69.5%	30.5c	57.5c	+27c	Strongly winning
Hormuz Jun overpriced	#1	Observation	88.5% YES	66.5% YES	-22pp	Tracking right

Three calls, three correct directions. Fictional portfolio +53.5% in 3 days. Small sample size, but the methodology is working: identify structural mispricing in geopolitical markets where the crowd underestimates inertia.

This is The Market Oracle, a weekly prediction market intelligence newsletter. Read more at https://site-two-nu-51.vercel.app

Prediction Markets Are on Fire: $540M on 2028, Arbitrage, and a Finland Surge — Issue #1

John Leslie — Fri, 24 Apr 2026 07:28:08 +0000

Issue #1 · April 22, 2026 · By John Leslie

This week: the Strait of Hormuz dominates everything, a 5.5-point cross-platform arbitrage gap on Senate control, and the Eurovision market is getting weird.

The Big Five: Markets Worth Watching

1. Strait of Hormuz — The $100 Oil Market

The single most important prediction market right now. Iran has "opened" and "closed" the strait multiple times since February. The latest: Iran declared it open April 17, then fired on ships trying to cross on April 18, closing it again within 24 hours.

April normalization: 9% YES (crashed from 38% four days ago. Called it at 38%.)
May normalization: 59% YES (down from 71.5% at the start of the week)
June normalization: 72.5% YES

Breaking (April 22): Trump announced an open-ended ceasefire extension, but the blockade remains fully in place. Iran re-closed the strait after briefly opening it April 17, with IRGC gunboats firing on Indian-flagged ships the next day. The US Navy seized Iran's cargo ship Touska and boarded tanker M/T Tifani. Iran is now demanding transit fees from all vessels. The negotiating positions remain far apart: the US wants a 20-year enrichment pause, Iran offered 5 years. Oil at $95/barrel.

2. 2028 Presidential Election — Way Too Early, Way Too Traded

$540M in volume already, $29M in open liquidity.

JD Vance: 19.1%
Gavin Newsom: 17.9%
Democrats to win (party): 60.5%

Democrats at 60.5% is a sharp move UP, driven largely by backlash to the Iran situation. Two months ago, this was below 50%.

3. 2026 Midterms — The Historical Pattern Is Screaming

Democrats to win House: 84.5%
Republicans: 15.5%

Historical base rate: the president's party has lost an average of 27 House seats in midterms since 1950. Is 15.5% for Republicans too cheap if the Iran situation resolves favorably?

4. 2026 Senate Control — The Arbitrage

The most actionable discrepancy across platforms right now:

Kalshi: Democrats 51% / Republicans 49%
Polymarket: Democrats 56.5%

That's a 5.5-point spread on the same question. If you have accounts on both platforms, this is a rare cross-platform opportunity. One of them is wrong by at least 2-3 points.

5. Eurovision 2026 — Finland's Surge

$97M volume, $15M liquidity.

Finland (Linda Lampenius, "Liekinheitin"): 36.4% (opened at 8/1)
France: 11.9%
Denmark: 10.2%
Australia: 7.3%

Finland has gone from longshot to overwhelming favorite. At 37%, the value question is whether this is a genuine lock or a momentum-driven overreaction.

Deep Dive: Hormuz — From 38% to 10.5% in Four Days

The April normalization market surged from 27% to 38% after Iran's April 17 announcement that the strait was "completely open." We called it overpriced at 38%. It's now 10.5%. Here's the timeline:

April 17: Iran's FM Araghchi declares the strait open to all commercial shipping during the ceasefire.

April 18: Iran reverses the decision. Iranian gunboats fire on tankers attempting to transit. The strait is closed again.

April 19: Iran's parliament begins drafting a law requiring ships from "hostile countries" to get explicit approval and pay tolls.

April 19: U.S. Navy seized an Iranian-flagged cargo ship. Tehran vowed retaliation.

April 20: Trump extends ceasefire to Wednesday evening (April 23 ET) but says further extension "highly unlikely." Market crashed from 38% to 29.5%.

April 20: Two Indian-flagged ships fired on by IRGC gunboats despite having clearance. India summons Iranian ambassador. Iran claims "unintentional" and "communication gap."

April 21: Trump says he won't extend ceasefire. Iran's speaker Qalibaf: "We do not accept negotiations under the shadow of threats." US boards M/T Tifani. April normalization crashes to 22%.

April 22 (AM): Trump reverses, announces open-ended ceasefire extension — but blockade stays. Iran demanding transit fees. Iran's FM Araghchi calls the blockade "an act of war and a violation of the ceasefire."

April 22 (PM): IRGC seizes two more vessels in the Strait of Hormuz for "disrupting order and safety." Negotiation deadlock: Iran refuses to talk until blockade lifts; Trump refuses to lift until deal. April normalization falls to 10%. May drops to 55%.

My call: April normalization is a NO at 10%. Practically resolved. Eight days left, 3-8 ships/day vs. 60 needed, and the IRGC is seizing more vessels as we speak. Our call at 38% has been vindicated.

May at 59% is still overpriced. My estimate: 30-40%. Today's IRGC seizures show escalation, not de-escalation. Iran calls the blockade "an act of war." The negotiations are deadlocked (Iran won't talk until blockade lifts, Trump won't lift until deal). ~800 vessels queued in the Gulf. This doesn't unwind in 5 weeks.

Confidence: Very high for April (practically resolved). Medium-high for May (escalation is structural, not tactical).

The Elephant in the Room: Insider Trading

The prediction market community is consumed by insider trading scandals:

A trader made ~$300,000 on Biden's pardon timing. The DOJ is investigating.
Another wagered $32,000 hours before U.S. Special Forces captured Venezuela's Maduro, netting $400,000.
40+ lawmakers led by Sen. Warren are calling for regulatory action.
A Trump-appointed CFTC official vowed to "aggressively investigate."

This is both a risk and a signal. Bernstein estimates prediction market volumes will hit $1 trillion by 2030. That doesn't happen if they get regulated out of existence. More likely: insider trading rules get clarified, which makes markets MORE legitimate, not less.

Track Record

Fictional $1,000 portfolio (started April 20): now worth $1,526 (+52.6% in 3 days). Hormuz April NO position up 56%, Hormuz May NO up 82%. Both calls correct direction. We called April at 38% — it's now 3%. May crashed from 69.5% to 44.5%.

This is The Market Oracle, a weekly prediction market intelligence newsletter. Read more at https://site-two-nu-51.vercel.app