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Why Is Polymarket a Scam? Our Investigation and Experience with the Platform
Polymarket is a scam, or just a dangerous tool? In this article, I break down — using fresh cases — why bet resolution on the platform is built so that an ordinary trader almost always loses.
On May 9–11, 2026, a three-day “ceasefire” between Ukraine and russia was in effect, at the latter’s repeated request, so the kremlin could hold its May 9 parade in moscow. On May 12, one day after it ended, russia launched more than 200 drones at Kyiv, Dnipro and Kharkiv. The war continued as before. But on Polymarket, the market «Russia x Ukraine ceasefire by May 31, 2026» with $14.5 million in volume resolved as «Yes». Even though the rules of that same market explicitly said that humanitarian pauses and any informal agreements did not count.
This is a fundamental problem in how the platform is built. In this article, I’ll explain why Polymarket, with $26 billion in quarterly volume, outsourced market resolution to a small protocol called UMA with a market cap of about $95 million. How whales make money from this, why you can’t really do anything about it, and why Ukraine blocked Polymarket back in December 2025.
In short: I do not recommend treating Polymarket as a serious tool. Details below.
Polymarket: scale and why it matters
Polymarket is now the largest decentralized prediction market in the world. A few numbers to show the scale:
Polymarket runs on Polygon, and all bets are settled in USDC. The key point for this discussion: Polymarket is a non-custodial service. The platform does not hold user funds and does not make the final decision on event outcomes. This architecture was a deliberate choice after the CFTC issued Polymarket a cease-and-desist order in January 2022 and forced it to pay a $1.4 million fine for operating as an illegal derivatives exchange. The team redesigned the system so that, formally, it controls nothing: trading goes through smart contracts, while outcome resolution goes through the external UMA oracle. Legally, this means: “we are not an exchange, we are just an interface.”
For the user, it means something else: when you buy «Yes», the decision on whether you won is not made by Polymarket. It is made by another project. Now let’s look at how that project works.
What UMA is and where this oracle came from
Before getting into the mechanics, we need some context. UMA (Universal Market Access) is a separate project founded in 2018 by Hart Lambur, a former Goldman Sachs trader. UMA was originally built as a platform for synthetic assets and derivatives, where users could create tokenized versions of Apple stock or the S&P 500 index. The synthetic-assets idea did not take off — Synthetix did it better and earlier — so UMA shifted toward the product that survived: an oracle for real-world data.
Today, UMA Optimistic Oracle serves more than Polymarket. Its clients include Across, a cross-chain bridge, Sherlock, a smart-contract insurance project, and other DeFi protocols. But Polymarket is its largest and most controversial client. If you look at the statistics, most UMA disputes come from Polymarket markets, because this is the one use case where outcomes are subjective and politically charged.
Polymarket and UMA are legally two different companies, but they are connected. In 2024, Polymarket and UMA announced a partnership with EigenLayer to develop a “next-generation” oracle based on restaking mechanics. Polymarket officially calls UMA its trusted oracle, while UMA officially calls Polymarket its largest client. In other words, they are formally independent partners, but without Polymarket, UMA would lose a large part of its reason to exist. That creates another hidden asymmetry of interests, which I’ll return to below.
How bet resolution works through UMA Optimistic Oracle
UMA’s architecture is called the Optimistic Oracle (OO), and it has two levels.
Level 1: optimistic assertion. When a market ends, anyone can propose an outcome — for example, “Yes” on the question of whether there was a ceasefire. To do this, they need to post a bond; on Polymarket this is usually $750 USDC. Then a 2-hour challenge period begins. If nobody disputes the proposal, the outcome is treated as correct, and the proposer gets their bond back plus a small reward. According to UMA’s statistics, only about 1.5% of proposals are disputed. This is the fast path, and it covers the overwhelming majority of markets.
Level 2: Data Verification Mechanism (DVM). If someone disputes the proposal, also by posting a $750 USDC bond, a vote begins. This is where the interesting part starts.
Only holders of UMA tokens who have staked them can vote. Voting happens in two stages:
1. Commit phase (24 hours): voters publish a hash of their vote. The real vote is hidden so nobody can simply copy someone else’s decision.
2. Reveal phase (24 hours): voters reveal their votes together with the salt used to create the hash.
Voting power is proportional to the number of staked UMA tokens. A decision requires a supermajority of more than 65%. Those who vote with the majority receive rewards, while those in the minority are slashed, roughly 0.1% of their stake. The slashing is small, but it creates a strong psychological effect: smaller voters are afraid to be wrong, so they vote “with everyone else” rather than according to reality.
After the vote ends, the result is returned to the Polymarket smart contract, the market closes, and payouts go to the winners. That’s it. Polymarket’s own help center states it directly: «Once finalized by UMA, outcomes are immutable». After UMA finalizes the resolution, the outcome cannot be changed. Polymarket cannot change it even if it wants to.
Now the key question: who are the people voting?
UMA’s structural problem: the numbers do not add up
This is where the circus begins. Let’s look at the numbers.
Think about that. The platform’s monthly volume is more than 100 times larger than the market cap of the project that decides all disputes on it. When the Zelenskyy suit story exploded in July 2025, one market with $242 million in volume was decided by people holding tokens worth roughly $95 million. In literal terms, it is cheaper to buy influence over voters than to lose a large market.
In March 2025, analyst Folke Hermansen looked into vote concentration and found that two whales controlled more than 50% of active voting power in an average vote. One individual held up to 7.5 million out of 20 million staked UMA, about 37% of the entire stake. This is not decentralization. This is an oligopoly covered with nice words about “truth-seeking”.
Separately: these whales often trade on Polymarket. In other words, they take a $1 million position and then vote in UMA in favor of their own outcome. The conflict of interest is built directly into the architecture. UMA says honesty is economically more profitable because if the system is discredited, the token will fall. That is a neat theory, but it breaks in specific situations where a one-off gain on a $7 million market is larger than the expected loss from a token drop.
And the final point: only UMA holders can vote. If you entered Polymarket, put $50,000 on a market, and are clearly right on the facts, you still have zero influence over resolution. The decision is made by completely different people, who may not trade the market at all or, more often, may be trading the opposite side. This is the core asymmetry from which the whole problem grows.
Fresh case: Russia x Ukraine ceasefire by end of 2026? ($220 million, May 2026)
The freshest and most revealing case. Let’s break it down.
Background. A series of «Russia x Ukraine ceasefire by 2026» markets had been trading on Polymarket for a long time. The largest ones had deadlines of May 31, 2026 and June 30, 2026. The rules were extremely clear, and I am not paraphrasing here. This is the direct wording:
«This market will resolve to “Yes” if there is an official ceasefire agreement, defined as a publicly announced and mutually agreed halt in military engagement, between Russia and Ukraine. Only ceasefires which constitute a general pause in the conflict will qualify. Ceasefires which only apply to energy infrastructure, the Black Sea, or other similar agreements will not qualify. Any form of informal agreement will not be considered an official ceasefire. Humanitarian pauses will not count toward the resolution of this market.»
The key part: humanitarian pauses do not count, informal agreements do not count, and the ceasefire must be a “general pause in the conflict” — a real halt to hostilities across the front.
What happened. On May 8, 2026, Trump announced a three-day ceasefire for May 9–11, timed to the May 9 parade in moscow. Both sides described it as a short-term pause in air strikes. A 1,000-for-1,000 prisoner exchange was also announced. Meanwhile, active assaults by russian occupying forces continued along the line of contact, so it was not even close to a ceasefire.
Was this an “informal agreement” without an official deal? Yes. Was it a “general pause in the conflict”? Obviously not: on May 12, one day after the “ceasefire” ended, russia launched more than 200 drones at Ukrainian cities. The war continued without any real pause.
How it resolved. The market «Russia x Ukraine ceasefire by May 31, 2026» with more than $200 million in volume resolved to «Yes». Trump posted about the ceasefire on social media, and the Polymarket team hid the markets, allegedly for technical reasons. While the markets were hidden, someone proposed «Yes» in UMA. Because the markets were unavailable on Polymarket, traders did not see it, and within hours all «Russia x Ukraine ceasefire by 2026» markets resolved to «Yes». UMA and the Polymarket team did nothing: the proposal went through, nobody disputed it. As a result, traders who followed the rules, bought «No» because the war had not actually ended, and believed that the rules mattered, were wiped out.
They do not matter. Whales holding «Yes» positions pushed this through UMA, and Polymarket did nothing. Again: «Once finalized by UMA, outcomes are immutable». Polymarket officially has no authority to reverse the result.
If you open that market now, the comments are full of complaints people keep posting almost every day: constant «refund?» and «scam». There will be no refund. This repeats the same pattern we will see below with the Zelenskyy suit and Ukraine mineral deal cases: the Polymarket team says “this is not market failure,” “we are working with UMA on improvements,” and returns nothing.
Why this is systemic. This case shows the entire fundamental problem. It does not matter how clearly the rules are written. If UMA voters vote against those rules, UMA’s decision wins. In other words, the market rules shown to you before you place a bet do not have legal force. The only thing with force is the vote of 20 million staked tokens held by a handful of people. And those people can vote in their own interest, because they can also take positions in the same market.
Voting dynamics. I looked at comments and discussions in the UMA Discord, including #evidence-rationale and #voting-discussion, where disputes are supposed to be discussed. There were attempts to dispute this market, but nowhere near the size of the $14.5 million position. Who is going to post a $750 USDC bond and risk losing it for someone else’s position? So the dispute lost, and the original «Yes» proposal was accepted. In the end, a market with formally clear rules resolved in a way that contradicted those rules, and «No» traders received no compensation.
Here is a typical reaction from Twitter: Ukraine Battle Map wrote, «Polymarket Traders who put $14.5 million worth of bets on a ceasefire between Russia and Ukraine are complaining after the market resolved to YES due to the 3-day ceasefire for May 9th parade. Even though the war will continue after it’s over». This was not a fringe thread. It was a public scandal seen by millions.
This is not a one-off case: other manipulations
Russia x Ukraine ceasefire is the hottest case, but it is far from the only one. Let’s briefly look at other examples to see that this is a pattern, not an accident.
Ukraine mineral deal with Trump (March 2025, $7 million)
Market: “Will Ukraine agree to a minerals deal with Trump before April?” The rules required official confirmation from the governments of the United States and Ukraine.
March 24–25, 2025. Trump publicly said he “expected the deal to be signed soon”. There was no official confirmation, and the deal was not signed. But the «Yes» price jumped from 9% to 100% in 24 hours. How? An anonymous whale using the address «BornTooLate.eth», who had accumulated 1.3 million UMA and became one of the top 5 voters, plus another whale with 5 million UMA split across three wallets and voting with 25% of the total weight, pushed the «Yes» decision through.
More than $7 million in the pool was affected, and traders who bought «No» lost everything. The crypto community called it “the most controversial incident in the service’s history”. The Polymarket team wrote in Discord that it was “not market failure” and there would be no refund: «We’re committed to building the future of prediction markets… we will build up systems». The system was never built. Two months later, the next scandal arrived.
Zelenskyy suit ($237 million, July 2025)
The loudest case. The market asked: “Will Zelenskyy be photographed wearing a suit between May 22 and June 30, 2025?” Resolution was supposed to depend on the “consensus of credible reporting”.
On June 24, Zelenskyy arrived at the NATO summit in The Hague wearing a black blazer, matching trousers and a shirt. More than 40 global media outlets, including Reuters, AP, BBC, Wired and others, called it a suit. Menswear expert Derek Guy told Wired that it met the technical definition of a suit. Polymarket Intel, a community account associated with the platform, tweeted «President Zelenskyy in a suit last night» on June 25, and later quietly changed its bio to “community ran”.
On July 1, UMA voted that it was “not a suit”, and the result was «No». Why? Because there was supposedly “not enough credible reporting consensus”. Even though 40 headlines from major outlets obviously form a consensus. A similar market in May had also resolved «No», and UMA voters cited that precedent.
Some numbers for context:
Menswear influencer Derek Guy separately placed $3.6 million on «No», apparently to potentially make $72,000. Anonymous X user Atlantislq wrote: “This is the biggest scam in PM history. Despite all the evidence, despite dozens of articles from major media outlets that are more than enough for consensus, they still sided with UMA manipulators and gave them all the money.”
Polymarket again did nothing. There was no refund. UMA co-founder Hart Lambur told Wired: “There is no evidence of UMA manipulation.” Formally, that is true — there is no direct evidence of collusion. But there is a structural reality: 30% of votes are held by 10 people, and when they want one outcome, that outcome wins.
Fort Knox gold, Israel-Lebanon, US-Iran ceasefire and others
These are only three of many examples that keep appearing:
If you look at Polymarket’s Trustpilot, the rating is 1.3/5 from 519 reviews. Most complaints follow the same pattern: “rules are not enforced,” “reality does not decide, whales do,” “whales buy UMA votes and change outcomes.” Yes, Trustpilot is generally where people go to complain. But when the complaints are this concentrated around one theme and match what independent analysts write, you cannot ignore it.
Folke Hermansen’s breakdown: why the system breaks
In March 2025, independent analyst Folke Hermansen published a detailed thread about manipulation on Polymarket. It is worth breaking down separately. His key points:
The UMA team publicly rejects accusations of manipulation. UMA co-founder Hart Lambur told Wired in July 2025: “There is no evidence of UMA manipulation.” Formally, that is true. There is no direct evidence of collusion between insiders, because such evidence is almost impossible to obtain when votes are anonymous. But there is a structural reality: 30% of votes in an average vote are held by 10 people, and that concentration itself makes the system vulnerable, regardless of whether there is malicious intent on a given day.
How whales make money from manipulation: the economics of the scam
To understand why this is not accidental, you need to look at the economics of manipulation from a whale’s point of view. Imagine a simplified version of how it works in practice, using the Russia-Ukraine ceasefire market as an example.
A whale with 5 million UMA tokens, worth about $25 million at the current price, looks at a market with $14.5 million in volume. During the panic after Trump’s announcement, the «No» price drops to 5–10%. The whale buys $1 million worth of «No» exposure for $50,000–100,000 because the price is low. Then, when resolution comes, he simply votes with his stake in favor of «No», persuades a few smaller voters — for example through the UMA Discord where disputes are discussed — and receives $1 million clean, because «No» wins.
There are two elegant parts to this scheme. First, the risks are small: a $750 USDC bond and a potential 0.1% slashing of the stake — about $25,000 in this example — against a potential $1 million profit. That is a 40x asymmetric bet with limited downside. Second, the manipulation is not technically illegal inside the protocol, because nobody violates UMA’s rules: everyone acts within a system that allows large stakers to vote however they want.
If you look at the history, this is exactly the pattern we see again and again. In the mineral deal case, a whale bought «Yes» positions at a low price of around 8–9%, then pushed «Yes» through UMA and earned the difference. In the Zelenskyy suit case, as far as it can be reconstructed, whales bought «No» cheaply when most people believed it was a suit, and then voted for «No». In both cases, the whale’s behavior is economically rational, and it becomes possible precisely because UMA’s architecture allows people with a position in a market to vote on that market’s outcome.
For context: compared with traditional finance, this would be like the NYSE allowing major shareholders of a company to vote on how to interpret its quarterly report. In the real world, people go to prison for that. In prediction markets, it is called “decentralization”.
Why a Polymarket user is powerless against UMA
The structural problem is that a Polymarket user has no real influence over UMA. They are different projects. Even if you deposit $100 million into Polymarket, a UMA whale with a $1 million stake can be more powerful than you in the system that decides outcomes.
Imagine the situation. You enter Polymarket, read the market rules — those clear ceasefire rules — and put $10,000 on «No». The market ends and resolves to «Yes» against the rules. You lose all $10,000. What can you do?
1. Dispute the proposal during the 2-hour challenge period? You can, by posting $750 USDC. But you will most likely lose the vote and lose that bond too, because UMA stakers with more tokens will say you are wrong. And if you are not sitting in UMA Discord and monitoring the market 24/7, you probably will not even see the moment when the proposal appears.
2. Vote in the DVM? You cannot. For that, you need to own UMA tokens and stake them. If all you have is USDC on Polymarket, you have no voting power.
3. File a complaint with Polymarket? You can, but the result is known in advance: your complaints will be ignored, “this is not market failure,” “we do not have the authority to change UMA’s decision,” “thanks for the feedback”.
4. Go to a regulator? Polymarket is non-custodial, legally “not an exchange,” and operates offshore. There is nowhere meaningful for a Ukrainian user to complain, especially considering that Polymarket is officially banned in Ukraine, which we’ll discuss below.
So even if you have a million dollars on the platform, your real voting power in the resolution system is zero. Decisions about your money are made in a system where you are not a participant. You simply pay into a pool that gets distributed according to other people’s decisions.
For comparison: on Kalshi, Polymarket’s main competitor in the United States, markets are resolved by the company itself, with external auditing and formal appeal procedures. If you believe Kalshi made a mistake, you can formally challenge the decision and it will be reviewed. Polymarket has no such mechanism by design: UMA decisions are final.
Why Polymarket changes nothing: it is not a bug, it is the architecture
This is where my own assessment begins. I do not believe the Polymarket team is unaware of the problem. It is discussed on Twitter every two or three months, every major scandal gets hundreds of posts in crypto media, and Atlantislq and Hermansen have written very accurate breakdowns. The team is not blind.
So why do they change nothing? Because the “non-custodial + external oracle” architecture is their legal shield.
Look at the timeline. In January 2022, the CFTC issued Polymarket a cease-and-desist and forced it to pay a $1.4 million fine for operating as an illegal derivatives exchange. The platform stopped serving the US and moved offshore. Then, when the CFTC gave Polymarket a no-action letter in January 2026 and allowed it to return to the US market, ICE/NYSE invested $2 billion at an $8 billion valuation. In October 2025, Polymarket signed an exclusive partnership with Dow Jones, and now Polymarket forecasts are shown on The Wall Street Journal, MarketWatch and Barron’s.
In other words, the platform gained legitimacy as a “source of truth”. But that legitimacy rests on the fact that Polymarket formally does not make decisions. If it starts interfering in resolutions, overturning UMA decisions or paying compensation, it becomes a classical exchange with all the consequences: full KYC, full regulatory burden, and responsibility for every decision. Right now it can say “it was not us, it was UMA,” and legally that works.
Polymarket is developing a new oracle together with EigenLayer and UMA, based on restaking. It was announced in 2024, but there has still been no real launch. The platform FAQ even says, “We anticipate rolling out a new rewards and oracle-resolution system later this year.” “Later this year” has already been turning into a second “this year”.
My assessment: they know about the problem, but changing the architecture is not in their interest. The current architecture works: $26 billion per quarter, an $8 billion valuation, a Dow Jones partnership, investment from NYSE. As long as money keeps flowing, the game is worth it. If UMA breaks individual markets, that is the users’ problem. The team is paid for volume, not for fairness.
Could everything change? Yes. If the CFTC or another major regulator looks at the next $200+ million scandal and decides that this is market manipulation, Polymarket will have a very unpleasant conversation. Or if large traders start moving to Kalshi, where this exact problem does not exist. So far, neither has happened.
Ukraine: blocked since December 10, 2025
For a Ukrainian audience, this is a separate and important context. Polymarket has been officially blocked in Ukraine since December 10, 2025.
Details: the National Commission for the State Regulation of Electronic Communications (NCEC) adopted Resolution No. 695, requiring Ukrainian internet providers to restrict access to polymarket.com. The reason was that Polymarket provides gambling services without a Ukrainian license. The initiator was PlayCity, Ukraine’s gambling regulator, which had previously blocked more than 4,500 illegal gambling websites.
The reasoning also separately mentioned that Polymarket allowed users to bet on events related to Russia’s invasion. By December 2025, about 240 markets about the war in Ukraine had already been completed on the platform, with total volume above $270 million. Another 120 active markets had more than $140 million in volume. The platform used data from the Ukrainian OSINT project DeepState without permission, while the Institute for the Study of War (ISW) criticized the fact that changes on its map were being used as a basis for bets on the occupation of specific Ukrainian cities.
The blocking is inconsistent in practice. Some Ukrainian providers enforce the resolution, others do not. Polymarket remains accessible through a VPN, but this violates the platform’s Terms of Service, Section 2.1.4, and Polymarket can freeze an account if it detects VPN use. Technically, its geo-detection goes beyond a simple IP check. If your account is blocked for VPN use, funds may be frozen for an indefinite period while a compliance review is ongoing. Documented cases of such freezes exist.
If you still want to use prediction markets from Ukraine, there are alternatives that are not directly blocked in Ukraine, but each has limitations:
Honestly, today there are few practical options from Ukraine for serious real-money prediction market betting. Polymarket is formally accessible through a VPN, but that is a gray zone with the risk of losing the account, on top of all the resolution problems described above. If you still go there through a VPN, the minimum you should do is not keep large balances on the platform, withdraw immediately after a win, and avoid subjective political markets.
Conclusion
I do not recommend using Polymarket as a serious betting tool. Here is the short version of why.
The architectural problem has not been fixed and is not being fixed. Bet resolution has been handed to the external UMA oracle, where voting power is concentrated among several whales who often have positions in the same markets. The Polymarket rules shown to you before you place a bet do not have legal force over UMA voting. I showed how that works in practice using three recent cases: the mineral deal, the Zelenskyy suit and the Russia-Ukraine ceasefire.
The Polymarket team knows this. It is impossible not to know when every two or three months another $7–237 million scandal spreads across crypto Twitter. But changing the architecture is not in their interest: it brings $26 billion in quarterly volume and legitimacy as a “source of truth” from Dow Jones, ICE/NYSE and the CFTC. As long as money flows, the system will not be changed.
Everything could change. If the CFTC or another major regulator looks at the next $200+ million scandal and classifies it as market manipulation, Polymarket will face a serious discussion. If the team finally launches the new oracle with EigenLayer as promised, maybe something will change. If large traders start leaving for Kalshi and Polymarket volumes begin falling, maybe the team will move. But none of that has happened yet.
Right now this topic is hyped, and you will see plenty of posts like “Polymarket is a scam” or “do not use it”. Most of them are shallow. The real problem is that Polymarket’s architecture structurally cannot guarantee fair resolution for subjective markets. On objective markets — Bitcoin above $100k, match winner, and similar questions — it works normally because there is nothing to interpret. But as soon as a question requires interpretation — “is this a suit?”, “is this a ceasefire?” — the system breaks in favor of those who hold UMA.
In my personal opinion, this platform is not safe for an ordinary trader. Even on markets where the outcome seems 100% obvious, UMA influence can push the result in another direction. UMA whales can manipulate markets very easily and leave regular traders without liquidity.
If you still want to bet on Polymarket, my advice is simple: choose only maximally objective markets with clear binary criteria, such as sports or price levels. Avoid geopolitics, elections and anything that requires interpretation of events. Do not put a large amount into one market, because in case of a scam you will not get anything back. And remember that the platform is officially blocked in Ukraine, so even if everything goes well, you are still in a gray zone.
Using Polymarket right now is at your own risk, in both the legal and financial sense. I do not recommend it, but the choice is yours.
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