A Manifold prediction platform user known as ‘Tumbles’ executed a trading scheme that involved borrowing debt, manipulating a market on his likelihood of paying those debts back, and losing millions in play money in the process. And now, he’s opening up about all the juicy details.
His story is a cautionary tale about the dangers of leveraging too much money and spiraling into debt. While Tumbles is only using play money, his schemes are the same kinds that ravage real-money markets. Tumbles also demonstrated shrewd strategic thinking and a consistent ability to persuade others, even bringing people to his side at the height of his debt.
The setting: Manifold
The setting was Manifold, a free-to-play prediction market platform that allows members to create their own markets, and have the final say in resolving them. Traders use a fictional currency called Mana that is regulated like a real currency to maintain its value among Manifold users.
Tumbles joined Manifold in September 2023 and started out placing small trades. But soon, he had an idea to multiply his winnings—but it didn’t pan out quite as he planned. The bad bets he made on political markets brought him from an account balance of about 870,000 Mana to -5.7 million Mana, a -755% drop in value.
That was only the beginning. Tumbles sat down with Prediction News at Manifest 2025 to tell us all about it.
Humble beginnings, whale dreams
One of Manifold’s unique features shows traders how their wagers will affect the market’s odds. In small markets, even a modest wager can move the odds 3%. A large bet can be even more disruptive.
As a new user on the platform, Tumbles began with about 1,000 Mana like all new players, but it wasn’t enough to make waves in markets. So, he asked a bigger player for a loan, another feature unique to play-money platforms like Manifold. The user agreed, securing Tumbles the first of what would be many Mana loans.
“They didn’t even give us specific terms,” Tumbles said. “There wasn’t a specific amount I owed. It was like, pay back what you feel…They’re [the large user] mostly just being nice, helping me out, [being] nice to the new guy. And then, you know, I spent all that and [I] want more. So I created a market that said, ‘Will Tumbles ever be late to pay back a loan?’”
The market on his debt repayment was the beginning of his main money-raising scheme. Because Tumbles created his own market on such a specific question, there was little trade volume. Even with a small amount of Mana, he could manipulate the market to make it appear that a consensus of traders believed him to be a trustworthy debtor. Then users would be more willing to make large loans to him, allowing him to make larger trades and repeat the cycle.
“I bet it [the market] down,” Tumbles said. “And I’m like, ‘Oh, this will be a tool to help me get more loans,’ because I can show it to people and be like, ‘Look, it’s unlikely I’ll be late to pay you back.’”
After going through Manifold leaderboards to solicit loans from users with high balances, Tumbles peaked at a net worth of about 870,000 Mana.
Interest on (supposedly) safe markets
One of the ways Tumbles planned to pay these loans back was to take advantage of the way Manifold paid interest.
“Part of the method to the madness was that Manifold gives out daily loans on your position,” Tumbles said. “At the time…2% of your position per day gets loaned out to you [in interest payments from Manifold].”
Open positions would result in small interest payments, so betting on “safe markets” would result in a steady stream of free Mana he could use to repay loans. Tumbles bet on markets with at least 95% probabilities. By leaving his positions open in markets he was unlikely to lose, Tumbles could earn interest without losing his money.
That was, until he took a 99-cent bet on Joe Biden being the Democratic nominee in 2024.
Tumbles’ debt chain falls apart
As questions grew about Biden’s viability as a candidate, the price on his nomination began to fall. Tumbles faced a key decision when the price fell to the high 80s.
“When that started to turn, I thought, ‘Oh, it shouldn’t be turning like [that],’” Tumbles said. “I just had a genuine opinion that I think he’s going to be the nominee, even as it fell a little bit. So this is like, let’s say like 88% of him being the nominee.”
Undeterred, he took out more loans to bet on Biden. “I decided, ‘I think my account is a crater if Biden’s not the nominee, so I should assume he is the nominee.’ So this is suddenly a really great deal.”
After Biden dropped out of the presidential race, it became clear that Tumbles’ wagers on Biden were not going to pay his loans back. He approached Manifold’s CEO, James Grugett, about a loan of Mana to make his account usable again so he could make trades and repay lenders.
“So, the pitch was that this doesn’t actually add any mana to the economy, it just makes my account usable, right?” Tumbles said. “And I didn’t actually have to end up paying him the [$69] fee. He gave it as a loan with no due date, and so that was the first bailout.”
In a later message on Discord, Tumbles also speculated that he “believe[d] James [Manifold’s CEO at the time] was also motivated by a desire to continue to see me keep trying things and making moves. Probably because my antics were seen to be a boon to Manifold’s culture.”
Unfortunately for Tumbles and his creditors, the next round of wagers put him deeper into debt. He made large bets on Kamala Harris winning the U.S. election, President Biden not pardoning Anthony Fauci, and the Conservative Party winning the Canadian election. The Canadian election was the final wager that landed Tumbles at a -5.7 million Mana net worth.
“Going into the Canadian election, I was offering to like, six times people’s Mana, three times people’s Mana, some heavy leverage. It was, like, ‘In three weeks, I’ll give you three times your Mana, or in one year, I’ll give you six times your Mana.’ I was giving crazy deals, and collected, like, another million Mana in loans off of those offers and then cratered on the [Canadian] election.”
Even that was not the end of Tumbles’ hustle to recoup his losses.
Games at Manifest 2025
During Manifest, the festival hosted many types of games in addition to the panels. Some event buy-ins and prizes were tied to Manifold’s play currency, providing some unique IRL chances to claw back some Mana.
At Manifest, Tumbles participated in a prisoner’s dilemma game with a 10,000 Mana buy-in.
He found the entry money by securing a 5,000 Mana loan from another user and by winning another 5,000 Mana in a trivia game that included questions about what his cat’s name was and his personal net worth. (Tumbles’ cat’s name was used as the name of another account he used to pay back lenders in the fallout of his loss in the Canadian election market.)
Once he secured the 10,000 Mana, Tumbles entered the prisoner’s dilemma game. In the game, a participant could split a 30,000-Mana pot with another contestant or try to steal it all for themselves. If both players tried to steal, then the pot would go to the game’s host, and no one would get any Mana. Players could also make deals with each other, the host, and the audience.
Tumbles managed to secure 62,000 Mana in loans from other users during his time in the prisoner’s dilemma game. He made a deal with the host to counter his opponent’s attempt to steal the pot. Tumbles also made a deal with an audience member who Tumbles participated in a Jeopardy event with earlier during Manifest. He made another deal with his opponent to go into debt with him.
Next, Tumbles wanted to find a way to leverage that Mana. His debts were worth $60,000 to $70,000 in USD, but Manifold’s co-founder, Stephen Grugett, offered him a $10,000 rate to buy the Mana necessary to repay his lenders. Tumbles wrote in a Discord message to Prediction News:
“I could in no way consider paying anything close to that myself, but acquiring that discount price created the possibility, however unlikely, that I might be able to convince some rich Manifest attendee to bail the whole thing out, perhaps by getting them invested in my story and framing it as a way to donate $10K to Manifold in appreciation to them as an organization. Long shot.”
Instead, Tumbles decided to put his 62,000 Mana at risk in a side bet on himself to win the event’s poker tournament.
Poker for 2 million mana
One of the side events during Manifest was a multi-day poker tournament. It was initially a free-to-play event. There was no prize until the final round, when organizers decided that there should be a one million-Mana prize and an engraving of the winner’s name on a plaque on the event’s campus.
The poker game was no-limit Texas Hold ‘Em. Blinds increased every 20 minutes at the final table.
Tumbles’ plan was to bet on himself to win, but besides luck, he also needed someone to make a large bet against him. Tumbles found his mark: “’Semiotic Rivalry,’ aka the singular best trader on Manifold.”
“I convinced Semiotic to bet a million Mana against me in the poker tournament. This is a bet Semiotic would never normally make in a million years. [He] would never take on such a massive risk with no viable way to hedge, but he was convinced in part because finally crushing the TFC [Tumbles Financial Complex] would be an extremely memorable way for it to end.”
So Tumbles staked his 62,000 plus other Mana he could get his hands on against Semiotic’s one million. Between the one-million Mana prize and Semiotic’s bet against Tumbles, there was now 2 million Mana Tumbles could win to help him settle his debts. But the cards didn’t go his way:
“At the big poker game, it was an eight-person table with a handful of extremely skilled players. I became the chip leader early on, and held onto the lead for about 10 minutes. But eventually it came down to a single hand…Another player with slightly more chips went all in on the flop and I called.”
Tumbles was behind with a flush draw, but would win the hand (and take a massive chip lead) if a six or a heart fell on either of the final two cards to come.
“But alas, no such luck.”
Why take the risk?
The saga of the Tumbles Financial Complex raises one overarching question: why take these risks and chase these schemes?
Tumbles pointed out that his personal risk remained reasonable. He’s only paid out a few hundred dollars “because of loans where I offered USD as collateral, but that’s a fair price for the amount of entertainment I’ve had.”
He wasn’t alone in finding the whole cascade of events entertaining. When I met Tumbles at Manifest, he was laughing with the Manifold employee who had briefly banned him from the platform.
Since his main risk involved fictional currency, Tumbles felt comfortable running scheme after scheme, showing analytical thought about his marks and self-awareness about how others would perceive him.
What did we learn?
Tumbles boiled his philosophy down to two principles:
“Principle one is that everything on Manifold is built on top of a pseudo-financial structure, and this nature must be respected. If you want other people to loan you Mana, find a way to offer them an attractive return on investment…
“Principle two is that people on Manifold and people involved in game shows are trying to have fun and be entertained. If you are forming a plan or strategy, it is extremely important that you arrange things so that the funniest possible thing would be if you won. If it is not funny for me to win, subtle forces will shift to make success more difficult. If it’s funny for me to win, people will come out of the woodwork to offer assistance.”
Tumbles’ appetite for risk and capacity for strategic thought pose a warning to real-money platforms. While Tumbles is comfortable pursuing his schemes because he uses a play-money platform, there are others who view real-money platforms with the same bemused sense of opportunity.
Tumbles’ story is also a lesson on how persuasive a charismatic character with an amusing, outrageous story can be—and how much belief in that story can cost—in real or play currency.
