#639
Heat Check
Published:
Apr 25, 2026
Author:
Sarah Parsons Wolter
Share:
On the evening of April 15, the temperature at Paris Charles de Gaulle climbed five degrees in twelve minutes. No nearby station registered anything similar. Just before the spike, a Polymarket account called "xX25Xx" placed roughly $120 in bets against an 18°C daily peak. The spike paid about $21,000. The account has since deleted its username. Nine days earlier, a different account made nearly $14,000 betting that Paris temperatures would peak at 21°C. Météo-France has filed a tampering complaint with airport police.
The sensor at Charles de Gaulle provides readings that pilots and air traffic controllers use to calibrate altitude, fuel use, and runway selection at France's largest airport. It also, thanks to Polymarket's contract design, settles daily temperature bets. The two Paris contracts drew roughly $1.4 million in combined wagers, more than double the typical April volume. On April 19, Polymarket moved its Paris reference station to Le Bourget.
The platform recently prohibited insider trading and market manipulation on its international platform, after an Israeli journalist said he received death threats from bettors over his reporting on Iranian missile strikes. The rules state that traders cannot influence the outcomes they bet on. At Charles de Gaulle, someone apparently decided that didn't apply to thermometers.
Portfolio News
Alcoa nears deal to sell dormant New York smelter site to Bitcoin miner NYDIG - Alcoa is in advanced talks to sell its Massena East site in upstate New York to Bitcoin financial services firm NYDIG, CEO Bill Oplinger told Bloomberg. Oplinger said the transaction should close in the middle part of this year, as the aluminum giant works to offload 10 dormant US smelter sites. The deal would make NYDIG the owner of the 1,300-acre facility, where it has operated with Coinmint since taking a strategic stake in Oct. 2024. Read more
Google for Startups Accelerator Africa announces 15 startups for class 10 cohort - Congratulations to portfolio company Termii, which was selected as part of a group of AI-driven innovators from nearly 2,600 applications across the continent. The program highlights startups working across fintech, agritech, health tech, mobility, and SaaS, with a shared focus on using artificial intelligence to address critical local and regional challenges. Read more
CapIntel brings tax impact into the investment proposal process - The new feature - a built-in capability that allows financial advisors to evaluate and communicate the tax impact of portfolio changes directly within the proposal process, eliminates the need for advisors to rely on separate tools and disconnected workflows. Read more
Oxio aims to use fintech to build Mexican prepaid market - Oxio plans to expand Mexico’s prepaid mobile market by targeting lower-income users with fintech-driven service bundles, to compete against incumbents like Walmart-backed Bait. Read more
Heat Check
France probes weather data tampering after surge in Polymarket bets - France's forecasting office flagged suspected tampering with weather sensors at the country's largest airport and referred the case to police, after detecting unusual readings alongside heavy betting on a popular prediction market. Read more
Did a mystery trader tamper with the temperature to win big on Polymarket? - France’s national weather service is investigating irregularities at a monitoring station at Paris Charles de Gaulle Airport after it reported anomalous temperature spikes. The spikes led to lucrative payoffs for some traders on Polymarket, the crypto-based betting platform. Read more
Arrest of U.S. soldier signals Polymarket’s wild-west days are ending - The arrest of a soldier charged with using classified information to place lucrative bets on Polymarket is a watershed moment for prediction markets, heralding a new era of stricter government enforcement of the wildly popular betting platforms. Read more
Industry News
How Bad Bunny used niche insurance to beat bad weather - Bad Bunny avoided multimillion-dollar losses in Medellin by using bespoke weather insurance. A team installed a temporary stadium weather station linked to a policy triggering payouts if rainfall exceeded thresholds, highlighting how niche insurance can mitigate climate risk for live events. Read more
Treasury and regulator to hold crunch talks with UK fintech unicorns - Sources also said the progress of the government’s deregulation drive and additional improvements to London listing incentives were likely to play a key part in meeting agendas. Read more
Revolut aims for $200b valuation in stock market listing - Should that happen, CEO and cofounder Nik Storonsky would become one of the richest people in the world, thanks to a lucrative incentive deal. Read more
Insurers move to cap cyber payouts related to AI and ‘LLMjacking’ - QBE and Beazley are among the groups that have proposed language for cyber insurance policies limiting payouts on AI losses. Insurers say such sublimits make clear that AI-related risks are covered in policies. But brokers and lawyers for corporate insurance buyers said they were concerned that new terms would eventually be used to reduce coverage for a range of emerging AI-related threats beyond LLMjacking. Read more
UK in talks with Anthropic over Mythos access for banks - Financial institutions are among those seeking to get expedited access to help strengthen their cyber security. In the meantime, groups were in discussions with Microsoft about securing “patches” or technical fixes that close off vulnerabilities found by Mythos. This has allowed companies to begin bolstering their software before they have access to the technology. Read more
DoorDash to offer stablecoin payments to drivers using Tempo - Tempo, co-founded by Stripe and Paradigm, wants to bring real-world payments onto its blockchain. The feature will allow faster and cheaper payouts by DoorDash, which processes payments between consumers, merchants and delivery workers across more than 40 countries. Read more
Kalshi to launch crypto trading with perpetual futures - Kalshi will enter the crypto market by offering perpetual futures, the most popular type of trading products, on crypto tokens such as bitcoin. Crypto perpetuals, largely off-limits to U.S. traders so far, are a type of risky product popular on overseas exchanges like Binance and Hyperliquid. They are futures contracts that allow traders to make leveraged bets on crypto prices without an expiration date. Read more
TikTok launches UK Creator Card with Visa - Meanwhile, TikTok continues to expand its financial footprint globally, having applied for Electronic Money Institution and direct credit licenses in Brazil earlier this month. Read more
Payward to acquire Bitnomial, creating a fully CFTC-licensed derivatives platform - Kraken entered into a definitive agreement to acquire Bitnomial, the first fully CFTC-licensed derivatives company in the United States built for digital assets, for up to $550m payable in cash and stock, in a transaction that values Payward’s equity at $20b. Read more
Yes, tokens do have real uses in finance - A thoughtful oped in the FT from Michael Roberts, chief executive of corporate and institutional banking at HSBC, about how tokens have so much power to reshape the financial ecosystem over the next decade and is already taking hold in areas including money, bonds, gold, funds, real estate and private equity. Read more
The billionaire math geek who turned AI into a money-printing machine - Alex Gerko’s edge as a trader comes from a supercomputer powered by geothermal energy in Iceland. Years before ChatGPT became a household name, his trading firm, XTX Markets, built an artificial-intelligence system aimed squarely at one goal: making money. That bold bet on AI has made XTX one of the most profitable players in the secretive world of algorithmic trading. Read more
How worried should Wall Street be about the stablecoin threat to deposits? - Stablecoins pose a theoretical risk to bank deposits, but their practical impact might be limited. The FT argues that yield alone won’t drive adoption; convenience matters. For now, deposits likely reshuffle, but future regulation could increase competitive pressure. Read more
Refinitiv to delete profiles of politicians’ grandchildren after lawsuit - Refinitiv will delete profiles of children listed as relatives of politically exposed persons after a lawsuit, highlighting tensions between money laundering databases, data protection laws, and risks of unfair debanking. Read more
New platform allows UK investors to hold crypto in ISAs again - This will allow investors to shelter any profits from capital gains tax, a particularly valuable protection for a highly volatile asset that is prone to deliver either large gains or large losses. Read more
Select Financings
Artemis - New York based provider of AI-cyber detection and automated response services raised $70m in Series A funding led by Felicis. Read more
Audrey AI - Dublin based AI platform for financial auditors raised $1.8m in Pre-seed funding led by Sure Valley Ventures and Delta Partners. Read more
BetHog - Belize based crypto casino and sportsbook raised $10m in Series A funding led by Will Ventures and RockawayX. Read more
Caruso - Dallas based fund administration platform for private markets raised $6.5m in Series A funding led by Icehouse Ventures and GD1. Read more
Hata - Malaysia based digital asset exchange raised $8m in Series A funding led by Bybit. Read more
Monk - Monk, which automates accounts receivable workflows, raised $25 million in Series A funding led by Footwork. Read more
Mosaic - New York based AI deal modeling platform raised $18m in Series A funding led by Radical Ventures. Read more
Petual - SF based financial audit software developer raised $20m in new funding led by Andreessen Horowitz and First Round Capital. Read more
Salmon - Philippines based consumer finance app raised $60m in new funding led by Spice Expeditions. Read more
Seapoint - Dublin based AI-powered financial operations platform for startups raised $8.8m in Seed funding led by 13Books. Read more
FinTech Collective Newsletter
Curated News with Context
Delivered every Monday, the weekly newsletter, produced by our team, provides a tightly edited rundown of global fintech news, along with a bit of our original analysis.