A $500,000 lesson: he made the right prediction but ended up in debt

Last week, the most talked-about topic globally was "the end of the U.S. government shutdown." After all, the global capital markets are closely watching the actions of the U.S.; when it reopens, it signifies potential policy changes.

On the largest prediction market, Polymarket, the market related to "when will the government reopen" saw over $100 million in trading volume, reflecting the market's attention. Interestingly, many people predicted the correct outcome but still lost money.

Let's rewind to November 12. On this day, good news kept coming: first, the White House press conference conveyed an optimistic signal, indicating that "the end of the government shutdown is likely to happen on Wednesday (November 12)." Then, on the evening of the 12th, President Trump officially signed the bill to end the shutdown, broadcasted live on television.

This ultimate certainty event, like other political events, triggered a strong market reaction immediately: the price of the Yes shares for "the shutdown ends on November 12" on Polymarket skyrocketed, peaking at $0.97. In the logic of prediction markets, this means the market consensus believes there is a 97% chance of this happening. Since the maximum can only reach $1, or a 100% probability, buying at $0.97 only yields the last 3%, but this 3% is a risk-free guaranteed profit because the event has already been confirmed.

In this frenzy of buying, the largest investor was a trader named YagsiTtocS (formerly known as Halfapound). He is a star figure in Polymarket's political sector, having participated in over 1,000 different markets from August to November 12, accumulating nearly $400,000 in profits, with a steadily rising profit curve and almost no losses.

(According to Polymarket's personal homepage, as of 6 PM on November 12, his historical trading profit curve was outstanding, with no significant drawdowns.)

Looking at his previous trading logic, apart from arbitrage, he was very adept at quickly buying in large quantities during significant, high-certainty news events.

In YagsiTtocS's view, the confirmation of the government reopening on the 12th perfectly aligned with his trading logic. Thus, he invested over $500,000, betting heavily on Yes at an average price of about $0.60. After Trump signed the bill, the price of Yes rose to $0.97. To him, this gamble was over; all that remained was to wait for the system to automatically settle his profits. He even continued to buy at high prices, believing this was no longer a subjective trade with risks, but rather "zero-risk short-term high-yield management."

Near Midnight: An Unfathomable Reversal

However, the story took a sharp turn from here.

After 10 PM that night, following Trump's signing of the bill and all news reporting the end of the shutdown, a bizarre scene unfolded in the market: the price of Yes began to fall instead of rise. This meant that some believed the market would settle as No on the 12th!

This left many puzzled: how could anyone think the shutdown "would not end" when the president had signed and the news was broadcasting?

The answer lies in the "market rules" that many traders tend to overlook.

The settlement of each market on Polymarket does not rely on what we commonly perceive as "facts," but rather on a single official information source that is clearly defined in advance. For the market "when will the government shutdown end," the rules explicitly state: the final arbiter is not the president's signature nor any news headline, but the U.S. Office of Personnel Management (OPM) announcing the "government operating status" on its official website.

The above image is a screenshot from Polymarket's execution rules for this market: the date OPM first announces "the federal government has ended the shutdown" (Eastern Time) is the standard. Specifically:

• The date of OPM's announcement is the standard, not the actual reopening date (for example: if November 10 announces reopening on November 11, the market will determine the reopening date as November 10);
• Partial shutdowns are also considered shutdowns;
• All status determinations are based on the OPM's operating status page (https://www.opm.gov/policy-data-oversight/snow-dismissal-procedures/current-status/)

In simple terms: only when the OPM website says "the government is open" will there be a settlement result in the market; if it does not say so, even if the president says it, it is invalid under Polymarket's rules.

Due to the lag in government system processes, the status on the OPM website was not updated immediately after Trump signed the bill.

Constraints of Rules and Emotional Collapse

At this moment, the most agonizing was YagsiTtocS. With only an hour left until midnight, his $500,000 hung by a thin line of rules.

As the date switched from the 12th to the 13th, the OPM website remained unchanged, and at this point, the Yes price for the 12th on Polymarket had collapsed, dropping from $0.97 to below $0.05. However, YagsiTtocS seemed unable to accept this reality: during the early hours of the 13th, he continued to buy the doomed Yes for the 12th, with prices ranging from $0.05 to $0.30. This was no longer a strategy but a "gambler's" operation driven by anger, unwillingness, and luck, attempting to fight against the cold rules by constantly "averaging down," further exacerbating his final losses.

When the market finally settled, YagsiTtocS's losses exceeded $500,000, making him the biggest loser in this market. This trade not only wiped out all his historical profits but also left him with a total loss of over $150,000, dropping him from the top of the platform's profit leaderboard to outside the top one million.

The Victor Who Understood the Rules

On the other side of this tragedy stood a trader named sargallot. Compared to YagsiTtocS's star aura, he had previously been inconspicuous, with an average trading volume of only about $200. As of November 12, his total profits were below $100. However, this seemingly ordinary trader became the biggest winner in this market, profiting over $100,000 by employing a completely different trading method from YagsiTtocS.

The secret to sargallot's success was simple: he read the rules carefully.

He realized that this market was not betting on "when the shutdown actually ends," but rather "when the OPM website updates its status," and he anticipated the possibility of administrative delays. Thus, on the evening of the 12th, when everyone was celebrating the news and driving the No price down to $0.07, he calmly bought in large quantities. When the OPM website failed to update in the early hours of the 13th, at 00:02, he exited at a price of $0.99, turning a small cost into an astonishing return.

A gamble, two outcomes. The star trader lost everything despite "predicting correctly," while the unknown trader filled his pockets by "understanding the rules." The $500,000 bought perhaps the most brutal and core lesson of this market.

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