The Brexit Short: How Hedge Funds Used Private Polls to Make Millions

Private polls – and a timely ‘concession’ from the face of Leave – allowed the funds to make millions off the pound’s collapse.

Farage Businessweek cover
Featured in Bloomberg Businessweek, July 2, 2018. Photographer: Olivia Harris/Reuters
 by Cam Simpson, Gavin Finch and Kit Chellel

At 10 p.m. on June 23, 2016, Sky News projected the words “IN OR OUT” across the top of a London building as an orchestral score ratcheted up the tension. “In or out—it is too late to change your mind,” declared Adam Boulton, the veteran anchor, seated in a makeshift studio across from Big Ben. “The polls have closed in the U.K.’s historic referendum on EU membership.” Election nights are major productions for British broadcasters, but Brexit was bigger, with Sky viewers watching worldwide.

After the dramatic intro, Boulton jumped straight in with a huge exclusive, declaring he had “breaking news.” Nigel Farage, the global face of the Brexit campaign, had given Sky what sounded like a concession. His photo and a statement filled the screen, as Faisal Islam, Sky’s political editor, read Farage’s words aloud: “It’s been an extraordinary referendum campaign, turnout looks to be exceptionally high and [it] looks like Remain will edge it. UKIP and I are going nowhere and the party will only continue to grow stronger in the future.”

In the next segment, Boulton delivered another exclusive. Joe Twyman, head of political research for YouGov, one of the U.K.’s most prominent polling firms, appeared on set with the results of an online exit poll conducted for Sky. He explained that the firm had been tracking the same voters—and they had moved farther into the Remain camp that day. Based on that, Twyman said, “We now expect that the United Kingdom will remain part of the European Union. It’s 52 percent Remain, 48 percent Leave, so it’s still close and it’s still too early to know definitely—but, based on the figures that we’re seeing, based on the trends that have occurred, and based on historical precedent—we think that Remain are in the strongest position.” As in past elections, Twyman added, voters had embraced the status quo on Election Day.

Just four minutes after the polls had closed, and with meaningful vote counts still more than two hours away, Sky had aired a concession from the world’s most prominent Brexit backer, buttressed by data from YouGov. In a few hours these “scoops” would prove spectacularly wrong, but in the meantime they spawned worldwide headlines, including from Bloomberg News and virtually everyone else. This one, which ran atop the U.K.’s leading news site, the Mail Online, was typical. Referring to Farage’s UK Independence Party, it read:

BREAKING NEWS: UKIP leader Nigel Farage sensationally concedes DEFEAT within seconds of voting closing as final poll gives Remain the edge 52% – 48% in historic EU referendum

The news pushed the U.K.’s currency up—herding investors toward a cliff hours ahead of one of the largest crashes for any major currency since the birth of the modern global financial system. Trillions of dollars in asset values would be wiped off the books, but not just yet.

At 10:52 p.m., the pound rose above $1.50 and reached its highest mark in six months. A few minutes later, Ed Conway, the Sky News economics editor, appeared before a giant screen showing the spike. The pound had been tracking polls for months, Conway explained. Whether they were on couches in London or at trading desks in Chicago, people watching Sky or reading headlines sparked by its coverage had every reason to think Remain would prevail. But not quite everyone.

Behind the scenes, a small group of people had a secret—and billions of dollars were at stake. Hedge funds aiming to win big from trades that day had hired YouGov and at least five other polling companies, including Farage’s favorite pollster. Their services, on the day and in the days leading up to the vote, varied, but pollsters sold hedge funds critical, advance information, including data that would have been illegal for them to give the public. Some hedge funds gained confidence, through private exit polls, that most Britons had voted to leave the EU, or that the vote was far closer than the public believed—knowledge pollsters provided while voting was still underway and hours ahead of official tallies. These hedge funds were in the perfect position to earn fortunes by short selling the British pound. Others learned the likely outcome of public, potentially market-moving polls before they were published, offering surefire trades.

Hedge fund managers, of course, try to beat the market by getting the best information they can. For exit polling data, that’s a tricky business. Pollsters have always sold surveys to private clients, but U.K. law restricts them from releasing exit-poll data before voting ends. While some of the practices discovered by Bloomberg fall into a gray area, the law is clear: It would have been a violation if, prior to the polls closing, “any section of the public” had gotten the same data the pollsters sold privately to hedge funds.

One person with questions still to answer is Farage, a former commodities broker who also went to work for a London currency trading company after he moved into politics. He twice told the world on election night that Leave had likely lost, when he had information suggesting his side had actually won. He also has changed his story about who told him what regarding that very valuable piece of information.

Bloomberg’s account is based in part on interviews over seven months with more than 30 knowledgeable current and former polling-company executives, consultants and traders, nearly all of whom spoke only on the condition they not be named because of confidentiality agreements. Pollsters said they believed Brexit yielded one of the most profitable single days in the history of their industry. Some hedge funds that hired them cleared in the hundreds of millions of dollars, while their industry on the whole was battered by the chaos Brexit wrought in global financial markets. Although confidentiality agreements have made it difficult to discover the identities of many of the hedge funds that bought exclusive or syndicated exit polls, at least a dozen were involved, and potentially many more, Bloomberg found.

The private exit poll that appears to have had the most clients was conducted by Farage’s favorite pollster and friend, Damian Lyons-Lowe, whose company is called Survation. It was sold to multiple clients and correctly predicted Leave, according to Farage and other sources familiar with the results. In an interview with Bloomberg, Farage said he learned of Survation’s results before making at least one of two public concessions that night, meaning there was a good chance he was feeding specious sentiment into markets.

Survation wasn’t alone. As YouGov’s Twyman predicted a Remain victory on Sky, three of his colleagues were watching from inside the London office of a hedge fund. In addition to the public exit poll for Sky, YouGov earlier sold a private exit poll to this fund, which provided data to traders that matched the results Twyman presented on television, effectively giving them an edge for betting on the rise in the pound sparked by his comments, according to sources familiar with the events. YouGov staff code-named it “Operation Pomegranate.” It charged the hedge fund roughly $1 million, according to knowledgeable sources. Separately, YouGov gave Sky its poll for free. The hedge fund did extremely well, according to three sources familiar with the situation.

Opinion polls published in the British press during the critical final days of the campaign helped voters make up their minds—about both whether to take part in the referendum and which side they were on. But the relationships between polling firms and hedge funds in the lead-up to the vote, and on the day, created an inherent conflict. With one hand, pollsters fed the public information that affected the outcome and moved the markets. With the other, they sold data privately to clients betting on market moves created by their public-facing polls.

Two years after the historic vote, the pound is back at $1.32, the bottom of the crash that morning. Inflation is up, and the Bank of England has said British households are poorer than they would have been otherwise. People remain divided, while the government of Prime Minister Theresa May is deadlocked over how to move forward.

Those aren’t the only unanswered questions. After the world asked how the nation’s leading pollsters could have been so wrong, British lawmakers launched an inquiry into whether misleading polls, in the referendum and other recent elections, were distorting democracy. But even members of a House of Lords select committee that looked into the subject had no idea that the companies they were probing had essentially become tools for firms wagering on the nation’s mood and votes. The Lords’ final report, released in April, made no mention of the relationships between pollsters and hedge funds.

George Foulkes, a Labour member of the upper House of Lords, was the driving force behind the select committee. On Monday, he called for lawmakers to initiate a Parliamentary inquiry into the “astonishing” practices revealed by Bloomberg. “The case for statutory regulation of polling companies is now overwhelming,” Foulkes said.

Brexit wasn’t even the first time it happened.

Play Video of Sky News Broadcast of Farage `Concession’ Statement and YouGov Poll

In the U.S., national newspapers and broadcasters hire for-profit pollsters for elections. But the news organizations oversee the design and analysis of the polls and brand them in their own names, giving them greater confidence in the independence of the data. By contrast, election polling in the British press is a brand-building affair for U.K. pollsters. Charging the press little, or even nothing, they use media polls as marketing tools to attract lucrative commercial clients. About 99 percent of the more than 4 billion pounds ($5.3 billion) in annual industry revenue typically comes not from elections but from marketing-related research—such things as, “Do you prefer Coke or Pepsi?” As the Lords committee report explained, election polls were “described by many of the witnesses as a ‘shop front’” for their commercial activities.

Polling firms found a way to tap deep-pocketed commercial clients for election polling during the Scottish independence referendum in September 2014. It all started when a pair of YouGov polls in the British press set off a national panic ahead of the vote. YouGov had nationalists closing the gap, and then, days later, jumping ahead with fewer than two weeks left in the campaign. Nervous investors sent the British pound and bank stocks down sharply. Shocked government leaders responded, just days before the vote, by promising a greater devolution of powers to the Scottish people if they stayed in the U.K., a pledge known as “The Vow.” Critics would later charge that misleading YouGov data, which proved fantastically off the vote, had shaped the future of an entire country.

The phones in YouGov’s offices rang like mad in the days between the Scottish polls and the referendum. Hedge fund executives were among those on the line. If YouGov was conducting another poll before the vote, traders said, they’d be willing to pay vast sums for a heads-up just 30 minutes to an hour before publication, according to two knowledgeable sources. Since news of the poll alone likely would move markets, the survey’s accuracy was meaningless; traders simply needed to know the results before they became public. They offered YouGov several multiples more than the newspapers had paid to commission the polls in the first place, the two insiders recalled. YouGov rejected these offers, the insiders said. Survation, along with at least one other pollster, saw other opportunities.

Survation organized and sold last-minute tracking polls and a syndicated exit poll for the Scottish referendum to some of the world’s biggest hedge funds, according to three knowledgeable sources. Clients included Brevan Howard Asset Management, then managing about $37 billion, Tudor Investment Corp. and the Japanese firm  Nomura Holdings Inc., according to one knowledgeable source. Brevan Howard even hired a second U.K. pollster, ICM Unlimited, and merged data from the two companies into its trading decisions, the source said. Pollsters at Survation and ICM streamed results throughout the day of the vote, allowing their hedge fund clients to place bets while voters were still casting ballots. Brevan Howard, Tudor and Nomura declined to comment for this story.

By early the next morning, it was clear that Scottish voters had rejected independence overwhelmingly. The YouGov poll that had sparked the most turmoil had missed the final mark by 6 points. Survation’s private exit poll, however, was accurate enough that its clients had what they needed to profit, according to knowledgeable sources. A lucrative  line of business was born for two industries.

In 2015, the Conservatives, under David Cameron, swept to dominance in the U.K.’s general election. Cameron had promised to hold a referendum on the nation’s membership in the European Union if he won. Hedge funds realized immediately that if the Scottish campaign had moved markets, a referendum on the U.K.’s membership in the world’s largest trading bloc might shake them to their very core. YouGov started getting hedge fund calls right away, according to sources familiar with the matter. So did the other polling companies. Buying a trading advantage through private exit polls on the day of the referendum was a primary interest, according to executives across the polling industry. But public-opinion-driven swings in the market during the campaign also could offer lucrative trading opportunities.

Pollsters brainstormed, inside their companies and with consultants, about the range of services they could sell, often at prices 10 or more times beyond the typical tab for political polls, several executives said.

But there were two potential obstacles to hedge fund exit polls. For starters, U.K. broadcasters normally air the results of their own exit poll at 10 p.m., immediately after voting closes. If this happened for Brexit, it might negate some of the advantages hedge funds had from private polls by giving the world definitive information at 10 p.m., according to polling firm executives. That’s because the official exit poll—jointly funded by the BBC, Sky and ITV, and based on 20,000 face-to-face interviews—is the authoritative projection of the day’s voting. It correctly predicted the last four U.K. general elections.

The face of the broadcasters’ election-night exit poll, its chief designer and interpreter, is a 64-year-old Scottish professor named John Curtice. He enjoys a rare level of trust across party lines and a cult following among political junkies. After the government set a referendum date, the academic spoke with broadcasters and they decided the usual exit poll was not feasible, recalled Sam Woodhouse, a BBC editor involved. They had made the same call for Scotland. Curtice would later tell BBC viewers that his predictive models relied on a comparable vote, and for Brexit there was none, making a credible exit poll an expensive and difficult proposition. However, hedge funds were spending the money to line up their own private polls—and Curtice was involved.

He told Bloomberg that polling company ICM paid him for his work on behalf of a hedge fund called Rokos Capital Management. Curtice said he participated “in a couple of phone calls with Rokos, where the design of the polling itself was discussed, alongside the modeling I was doing.” He said he also had discussions solely with ICM. The company conducted an exit poll for Rokos, according to Curtice and another knowledgeable source. Curtice said he didn’t help conduct the poll on the day, nor did he help analyze the results. He said his primary role was to help ICM build a model that enabled the hedge fund to predict the likely outcome of the vote as localities began reporting results. Rokos could then calibrate its trading strategy off a mixture of polling data and results as they started coming in after midnight. Alan Kilkenny, a Rokos spokesman, declined to comment.

Another member of Curtice’s media-polling team, Steve Fisher, an associate professor at Oxford University, helped Survation design the syndicated exit poll it conducted for multiple hedge funds, according to two sources familiar with the matter. Fisher declined to comment.

Curtice also is president of the British Polling Council, a voluntary, self-regulating body that counts YouGov, Survation, ICM and the nation’s other major pollsters among its members. The lack of a formal exit poll for broadcasters made it possible for the group’s members to earn record revenues from Brexit, some polling company executives said. “The claim sounds plausible,” Curtice said, “but I am not in a position to verify it one way or the other.” He also said he was not aware of specifics about other hedge fund polls, or their results, including ICM’s.

Another potential obstacle to hedge fund exit polls may have been more significant: It is a crime in the U.K. to “publish” any exit poll results prior to 10 p.m. Hedge funds wanted data streamed to them throughout the day so their own data experts could track trends, and so they could make bets while people were still voting. But the law broadly defines “publish” as making any data “available to the public at large, or any section of the public, in whatever form and by whatever means” [emphasis added]. Gavin Millar, QC, a public law expert who consulted for a media client about the law in a previous election, said it has never been tested, so conduct potentially triggering charges is a legal gray area. (Millar has represented Bloomberg LP in unrelated matters.) On the books since 2000, the crime carries a penalty of up to six months in prison and a potentially limitless fine, he said.

Inside YouGov, concerns about the law limited the company’s potential offerings, according to an email that YouGov founder Stephan Shakespeare shared with Bloomberg. YouGov’s chief financial officer spoke to lawyers and decided that a single hedge fund could not be considered “a section of the public” but that multiple hedge funds getting the same exit poll might cross the line. Other polling companies appear to have interpreted the law differently.

How the Pound reacted to BrexitAs the vote neared in June, Leave’s rising support in polls sank the pound, and hedge funds intensified their negotiations with YouGov and other pollsters. Given the amount of money on offer, several polling company executives said they believed nearly everyone in their industry ended up working for traders in one capacity or another. In the runup to the referendum, a handful of press accounts referenced that hedge funds were in the market for, or had hired, pollsters, but none provided details. Bloomberg has confirmed that the following companies were hired to conduct private exit polls: YouGov, Survation, ICM, a Birmingham company called BMG, and ComRes.

Another company, Populus, conducted an exit poll for Michael Ashcroft, the billionaire former deputy chairman of the Conservative Party. Ashcroft, who runs a bank in Belize, routinely commissions polls that he later releases to the public, as he did on Brexit. Andrew Cooper, the Populus founder and former director of strategy for David Cameron, also said his firm was paid to create a polling-based model that enabled a financial client to calibrate trades as results came in after midnight, but he declined to name that client, citing a non-disclosure agreement.

Beyond the broadcasters’ exit poll team of Curtice and Fisher, several other leading U.K. academics also worked for hedge funds—either directly or for the pollsters in their employ. “I was running exit polls on the day for hedge funds,” said Matt Goodwin, a professor at Kent University and the author of books about UKIP and Brexit. He declined to elaborate, citing non-disclosure agreements.

Shakespeare founded online pollster YouGov in 2000 at the dawn of the information-technology age. Thanks to its prolific use of news media polls to draw commercial business, YouGov developed one of the highest profiles of any U.K. polling firm. One of its most successful commercial products is called the BrandIndex, which “measures public perception of thousands of brands across dozens of sectors,” giving stock pickers a leading indicator of a company’s share price. In 2008, YouGov set up its own hedge fund to trade off the data, but the ensuing financial crisis sank it.

In YouGov’s early days,  a company director tried to get attention by using its online surveys to gamble on a television talent show, Pop Idol. YouGov announced a prediction that crooner Will Young would win with 53 percent, and the director bet on the singer. Young won the contest with 53 percent of the votes. A British tabloid then started buying talent show polls from YouGov. The company later banned employees from betting on its work, but pollsters noticed something: Their public surveys were moving the odds set by the U.K.’s bookmakers. Professional gamblers offered cash for leaks, just as hedge fund traders would do later during the Scottish referendum, according to senior executives. They wanted advance word so they could bet on the changing numbers, not the outcome. YouGov turned down all such offers, Shakespeare said, adding that his company is proud of operating ethically.

YouGov’s staff realized that people could profit off a poll by learning its results in advance, rather than betting on the outcome of the underlying event the poll was meant to predict, according to sources familiar with the events.

As the EU referendum approached, YouGov executives discussed the idea of selling an exit poll exclusively to a single hedge fund for a huge premium—what would become “Operation Pomegranate.” The hedge fund exit poll would help traders predict the results of the public one YouGov would release on TV later that night, according to two knowledgeable sources. The hedge fund could then make trades with high confidence, because it could predict how Twyman’s call—52-48 for Remain—would likely move the market, the sources said.

Shakespeare confirmed that the polls showed the same thing. But he said it was never his company’s intention to sell private polls in order to help clients predict the outcome of a public poll. Shakespeare also said the “trading strategies of hedge funds are extremely secret. We did not know their strategy and still don’t.” YouGov’s hedge fund client “did not know what the Sky poll would say,” Shakespeare added. “They had their own independent—more detailed and bigger data. But the outcome was the same.”

One reason YouGov could charge so much—roughly $1 million—was because it would air the only public exit poll that night in the time slot normally designated for Curtice’s authoritative survey, the sources said. Indeed, YouGov was able to charge much more than what other polling company executives said they collected. Shakespeare said the price had nothing to do with his firm’s public polling. “We try to get a fair price for our data’s superior quality, volume and detail,” he said. Shakespeare declined to say how much YouGov charged Sky for the broadcast poll, but people on both sides of the transaction said it was free.

On the night of the vote, though, one final question loomed. YouGov’s agreement with Sky specified that if the results were within 5 points, the pollster had the option of saying on air that the vote was “too close to call.” If Twyman said that, the pound’s movement probably would have been less predictable. But that potential was removed, according to two sources familiar with the events, when Shakespeare told Twyman by phone to make the call for Remain. Shakespeare said he urged Twyman to speak with caution, adding that his decision was based on his confidence in the data and was “in no way connected with any known trading strategy of any hedge fund.”

In the runup to the referendum, YouGov also sold regular online polls to hedge funds, according to clients and others involved. The data effectively provided hedge funds with an early indication of what YouGov would publish later, according to one source familiar with the matter. Shakespeare said that this was never his company’s business strategy. He also said all of “our data predicted the same result. There was never any difference between what our clients knew and what the public knew.” Sky declined to comment.

Shakespeare said any betting strategy based on predicting how public polls might move markets “would be extremely risky.”

YouGov wasn’t the only pollster launched with a boost from talent show betting. Lyons-Lowe, a former hedge fund salesman, started Survation in 2010, in part to gauge the public’s support for contestants on Simon Cowell’s X Factor so he could wager on the outcome, according to two people familiar with Survation’s business. The company got its big break in political polling when it was hired by Nigel Farage and UKIP after its surveys showed more support for the anti-Europe party than those of more established pollsters. “I learned more in one lunch with him about polling than I’d learned from anybody in 20 years,” Farage recalled of their first meeting, held before a 2013 election.

The organizations grew so close that Survation once based its phone operators in UKIP headquarters, according to a knowledgeable source, and Lyons-Lowe became a friend and key adviser to Farage. “He is a genius—flawed, but a genius,” Farage said of Lyons-Lowe in his interview with Bloomberg, declining to elaborate.

On June 23, the day of the EU referendum, Farage and his team gathered at the London home of a UKIP adviser. Their actions that day have been retold in two books. The Bad Boys of Brexit is an insider account penned by Arron Banks, a main financier of Farage’s unofficial Leave campaign who was with the UKIP leader that day. The second account is contained in All Out War: The Full Story of How Brexit Sank Britain’s Political Class, by journalist Tim Shipman. It is based on an interview with Chris Bruni-Lowe, who was Farage’s chief political adviser and was with Farage and Banks on June 23.

The published accounts differ, but both say that Farage had learned the results of an unidentified, financial-services exit poll well before the polls closed at 10 p.m. These accounts also say that Farage learned the results before giving his concession statement to Sky at roughly 9:40 p.m., which the network then aired within seconds of the polls closing at 10 p.m.

Farage, who had not detailed since that night what he learned or how he knew it, told Bloomberg that the only external exit poll results he received on June 23 were Survation’s—and that Lyons-Lowe gave them to him. “He got it right,” Farage said of Lyons-Lowe. “And whoever, whichever clientele, whichever City hedge funds paid him that day, did very well out of it.” Others with knowledge of the results also said that Lyons-Lowe’s hedge fund exit poll accurately called the vote for Leave.

Farage, however, repeatedly told Bloomberg that he learned the results from Lyons-Lowe’s poll only “minutes after” Sky put his market-moving statement on the air just past 10 p.m.—not before. “That would have been, that would have been—for he and I to have spoken ahead of that 10 o’clock—would have been wrong at every level. Wrong for me, wrong for him, just would have been wrong,” Farage said. After saying he heard the results from Lyons-Lowe, Farage then changed his story, saying they came not from Lyons-Lowe personally, but from someone affiliated with Survation’s operation. (In a subsequent telephone interview, Farage again changed his story to say he had indeed spoken by phone with Lyons-Lowe. He said Lyons-Lowe intimated that the U.K. had voted for Leave, but he didn’t share specific data. Farage also said that, at the time, he didn’t believe what Lyons-Lowe had told him, and that another contact, whom he declined to identify, mentioned other polling showing Remain would win.)

In response to questions, Lyons-Lowe released a statement: “Survation Ltd. has established itself as a leading opinion poll and research provider, including in respect of referendums and other elections where innovative methodologies are required. We work regularly for a wide variety of newspapers, private clients and political parties. Survation Ltd. does not comment on any confidential client work.”

Farage called his statement to Sky “a terrible mistake,” but he also asserted that he did not give the network’s reporter a true concession. “It was an acceptance that we might not win, but it was hardly, but it was not how—they [Sky] overegged it. They overegged it. But that’s journalism,” he said.

What Farage could not explain, however, is why he gave a further concession about 70 minutes after the Sky broadcast, which not only echoed the statement aired on Sky, but was more adamant. In it, he also specifically cited a financial-firm exit poll as his reason for conceding.

Farage made the second concession in an interview with the Press Association, a U.K. news cooperative. Its report says: “Mr. Farage told the Press Association: ‘I don’t know, but I think Remain will edge it, yes. The massive increase in voter registration will be the reason for that.’ Asked if he was just experiencing election-night jitters, the UKIP leader replied: ‘It is a calm and rational feeling. If I am wrong, I would be thrilled. But it is what we have seen out and about, and what I know from some of my friends in the financial markets who have done some big polling.’” Bloomberg sent a series of headlines from that interview to its more than 300,000 financial clients around the world.

Farage rejected the idea that his concessions were aimed at moving the markets for anyone. But he also laughed about helping to push the pound higher ahead of its crash, a role he seemed to relish. “Yeah, and a good thing—good thing,” he told Bloomberg, adding that those “who trade short-term markets and lose money shouldn’t complain, because that’s the game. That’s the game.”

The pound offered the simplest play for short sellers looking to profit from the Brexit vote, vs. stocks or other assets. That’s because currency markets are the deepest, most liquid markets in the world, making them the easiest to trade. In this case, another factor also made it easier. As early as January, banks started downgrading their forecasts for the pound to reflect the risk of a Leave vote. JPMorgan Chase & Co. lowered its estimate to $1.32. Other banks made similar predictions. The marker helped international financial institutions hedge their risks, but it also gave short sellers a target.

There are many ways to bet on a currency crash, but the main vehicle for many hedge funds is derivatives. Their existence means that hedge funds buying exit polls didn’t need to get it right. They just needed to be more right than everyone else. Many were, because even exit polls that got it wrong gave hedge funds underlying data that pointed to pro-Brexit trends, according to those involved. One example: Even though YouGov decided not to declare it “too close to call,” its hedge fund client still could use the underlying raw data to get its own, potentially more advanced analysis, Shakespeare said.

Pollsters involved in the exit polls say their hedge fund clients had them stream data in regular intervals—as often as every hour—while voting was underway. One veteran London hedge fund boss, who said he sat out Brexit, said that having data just one hour before official tallies that showed the vote was close, or leaning toward Leave, would be like a lifetime for an experienced trader. For the best ones, he said, 20 minutes was more than enough.

Derivatives allow traders to benefit greatly from market moves with only a small sum on the table. (Losses also are amplified.) They are priced to reflect the market’s mood, so the Remain sentiment in the polls leading up to the vote, and after Sky’s opening minutes, made short bets cheap. The groupthink effect was what traders on currency desks call “keeping the pigs hungry.” A short seller needs a world of voracious buyers to think he’s the dumb one, for as long as possible. The more unexpected the victory, the bigger the potential profit for the hedge funds.

Pre-election polls published in the British press effectively smoothed the way. In the final four days, YouGov, Survation, ComRes and BMG all published polls showing Remain ahead. Some of their polling specifically was cited by currency analysts for moving the pound higher in the final week. Populus showed Remain winning by 10 points, making it the most off-base poll released. That one came out the day of the vote. None of the pollsters publicly disclosed that they were simultaneously working for hedge funds that stood to make massive profits if the results went the other way—against all expectations.

Effect of the concession with YouGov pollThe effect intensified on the night. The Sky News “exclusives” from Farage and Twyman filled an information vacuum created by the lack of the formal broadcasters’ exit poll headed by Curtice. The pound was so buoyed that Bloomberg sent out a chart to financial clients worldwide showing the currency “heading for its best week against the dollar since 2009.” That was at 11:32 p.m.

Just before midnight, the market got nervous, and the pound dipped below $1.49 for the first time since 10:05 p.m. Just after midnight, Newcastle reported for Remain, but at a much narrower margin than expected. Minutes later, the price of derivatives tied to a declining pound likely shot up, as measured by IG Fund, an online exchange for currencies. IG’s rolling prediction instantly dropped to just a 69.5 percent probability for Remain, down from 91.5 percent. Anyone holding derivatives before Newcastle who had shorted the pound, however, was already in the money.

At 12:16 a.m., the city of Sunderland dropped a bomb—61.3 percent had voted for Leave, instead of the roughly 53 percent predicted by polling models. The pound plummeted one minute later, hitting $1.43. The pattern repeated over the next five hours.

Inside its hedge fund client’s office, YouGov had three pollsters working through the night. They spoke directly with the hedge fund’s analysts, according to an inside account confirmed by Shakespeare. The analysts would duck in and out of the room, asking YouGov’s team to quantify, from zero to 100, how confident they were in their latest predictions, according to a source familiar with these events.

At 5:28 a.m., the pound bottomed out at $1.32, the mark cited by JPMorgan back in January. However, something was significantly off, according to an analysis of data later compiled by researchers at the Swiss Finance Institute. They concluded that there was so much false sentiment for Remain built into the market that night that the pound was at least one hour slower in reaching its bottom than it should have been, and slower than even the dumbest computer model they could create. They attributed this to a herding mentality similar to what happens in a financial bubble. All of that pro-Remain sentiment made for a lot of hungry pigs.

Farage on Sky News

Brexit’s Big Short: Hedge Funds Hired Pollsters and Cashed In

If public polling up to and on the final day inflated a bubble, how might private polls have helped traders? In at least two ways, according to pollsters involved, hedge fund traders and consultants. First, commission a private poll that closely tracks what will be released to the public, as in Operation Pomegranate, tipping traders in advance to how the market may move. Second, get better data than the public has, allowing traders to see if the market’s faith in the pound is misplaced, or the currency is overvalued. Both strategies come with some risk, but because the trader is betting against the prevailing market sentiment, the bet is cheap and the potential payout is high—just the sort of situation hedge funds love. For traders, it doesn’t matter if the pollster’s ultimate exit-poll prediction is wrong (as some were on Brexit night). Hedge funds’ internal models, some far more advanced than anything in the polling industry, fed on raw data, such as turnout in specific regions, that allowed them to make smarter bets. “They are looking for a slight edge—they don’t expect you to be 100 percent accurate,” said one pollster.

Rokos, which had worked with ICM and Curtice, ended up making more than $100 million, or 3 percent of its entire value, in a single day, according to the results Bloomberg first reported in the wake of the vote. Brevan Howard, which at a minimum bought exit-polling data from ComRes, made $160 million on June 24 alone. Brevan Howard declined to comment.

While the identity of YouGov’s Operation Pomegranate hedge fund client remains unclear, knowledgeable sources identified two clients for its pre-election polling. They are  Capstone Investment Advisors and Odey Asset Management. Capstone, then managing more than $5.2 billion, made about 1.7 percent of the value of its biggest fund off its Brexit trades, Bloomberg reported after the vote, citing a knowledgeable source. Some of that was specifically attributed to bets placed on price swings leading up to the referendum. Capstone declined to comment for this article. Odey’s eponymous founder is Crispin Odey, who was both a top fundraiser for Farage and a leading contributor of campaign cash to the pro-Brexit side. His firm made about $300 million from Brexit. “There’s that Italian expression,” Odey boasted to the BBC of his Brexit bounty: “‘Al mattino ha l’oro in bocca’—the morning has gold in its mouth.”

In an interview with Bloomberg, Odey said the private polling purchased from YouGov ahead of the vote was valuable, though not definitive, because there was still a high level of uncertainty about the outcome. He said his firm didn’t buy an exit poll on the day. “Everyone is going to try to improve the information they have,” he said of hedge fund surveys. “That’s the arms race.” But, he said, it shouldn’t be possible for some traders to pay more for better information. “The idea of public markets is that you have equality. If you don’t, then one has to be worried about that.”

At least six other hedge funds were among those negotiating or shopping for polls, according to interviews with polling executives, including one who accessed his email archives for Bloomberg during an interview. These included  Arrowgrass Capital Partners, Element Capital, Maven, PointState and TSE Capital Management. The same polling executive said that at least three more— North Asset Management, SPX Capital and Vigilant—were trying to obtain information regarding the timing of media-published polls. It’s not clear which, if any, bought polling. All of these firms declined to comment or did not respond to requests for comment.

Dawn Hands, the managing director of pollster BMG, said her firm “does not comment on the detail of any research conducted privately, nor name any of its private clients.” Gregor Jackson, research director at ICM, confirmed that the company had private clients in the Scottish and EU referendums but declined to comment further. A ComRes spokesman also declined to comment.

Capitalizing on a wave of market-moving political volatility stemming from voter discontent across the world, some of the pollsters involved in Brexit have tried to replicate their success beyond the U.K. Survation worked for financial services firms in the Italian election in March, when two populist Euroskeptic parties won, according to a knowledgeable source. There could be more to come for the U.K., too, with George Soros, among others, pushing for a new EU referendum.

Even if that doesn’t happen, Prime Minister May’s government remains seized by internal divides over Brexit, leading to predictions of a new snap election. A pollster who profited off the EU referendum said, “That would be something that would have the potential to move the markets around” again, because a snap election would really be about implementing Brexit.

Asked for his prediction, the pollster demurred. He said he will keep his opinions to himself until hedge funds come calling again.

(Updates with call for Parliamentary inquiry in 16th paragraph. Previous version corrected poll number on Scottish vote.)