Over the last few months, sealed wooden boxes have been arriving in the holds of commercial flights from London to New York, strapped up and tightly packed against tampering. When they land stateside, they are collected by trucks whose drivers, generally, don’t know what they’re hauling. 

What’s inside are stacks of silver bars that traders, fearing that tariffs from the U.S. government are imminent, are loading onto planes to rush into America.

Gold is commonly flown between key global trading hubs including London, New York, Zurich, Hong Kong and Shanghai. Cheaper, bulkier silver is typically sent by ship.

Many market participants doubt that precious metals will be included in any tariffs, but that has not stopped traders from seeking to close out their exposure.

But the Trump administration’s threats of tariffs have created unprecedented dislocations. U.S. silver futures have spiked to a premium of more than $1 per ounce, making air freight viable, and sending traders rushing to get metals into the U.S. before the new trade measures are announced, according to traders.

“It is highly, highly unusual,” Philip Newman, industry veteran and founding partner at the consultancy Metals Focus, said. “It’s the first time I’ve heard of that in terms of the London to New York route.”

Gold and copper are also pouring into the U.S. Futures have surged above their international benchmarks since President Donald Trump’s election victory in November, creating an opportunity for the handful of trading houses and banks that are capable of moving large volumes of metal into the U.S. at short notice, and huge risks for investors who can’t.

Nearly 14 million ounces of gold, worth $38 billion, have flowed into the depositories of New York’s Comex futures exchange since election day, along with 45 million ounces of silver. Huge volumes of gold have been exported out of Switzerland, while the rush for bullion led to weeks-long queues to withdraw the metal from the Bank of England’s vault into the custody of private banks, according to people familiar with the matter.

Gold hit an all-time high January 29, as traders looked for safe havens as the Trump administration’s tariffs loomed. 

The rare trade flows reveal how the commodities industry is being upended by Trump’s trade policies, even before he makes good on repeated campaign pledges to impose hefty tariffs on trading foes and allies alike. He had signaled that levies could come as soon as February 1, creating a further incentive to fly metal into the U.S. before the window of opportunity slams shut.

The White House said on January 31 that President Trump intends to move ahead with plans on February 1 to impose 25% tariffs on Mexico and Canada, and a 10% levy on China, denying a report that he planned to delay the implementation by a month.

Trump has also said he intends to impose across-the-board duties that are “much bigger” than the 2.5% figure previously suggested by Treasury Secretary Scott Bessent. Mexico is a big supplier of silver to the U.S., accounting for 41% of U.S. imports by volume in 2023, according to estimates from Morgan Stanley.

Gold is typically moved from one trading hub to another in the cargo hold of passenger aircraft. There’s a limit on how much can be moved on one flight — not because of its weight, but because of its value, as insurers will only cover a certain amount on any one plane. It’s not unheard of for nations to send military planes to ship their gold around the world, complete with armed escorts.

Still, gold can’t simply be flown from London to New York to deliver against Comex, because the two markets use different sizes of bars. In the London market, 400-ounce bars are the standard, while for the Comex contract traders must deliver 100-ounce or kilobars. That means gold to be delivered against Comex typically comes from large refineries in Switzerland or trading hubs in Asia where kilobars are popular.

For silver, there is no such size issue: both the London market and Comex deal in hefty 1,000-ounce bars. And while in normal times, silver is too low in value to be worth the cost of transporting it by plane, market disruptions can upend the normal economics of commodity trading. In the 1980s, for example, traders even put much-lower-value aluminum on to planes in order to more quickly capture an arbitrage.

Many market participants doubt that precious metals will be included in any tariffs, but that has not stopped traders from seeking to close out their exposure. The last time the precious metals markets saw dislocations on this scale was during the early days of the pandemic. Back then, flights were grounded, upending the gold market and leading to bumper profits for those who could deliver metal in the U.S., and heavy losses for those who couldn’t.

U.S. copper imports have also jumped in recent months, fueled by rare bulk shipments from Chile and a trickle of metal flowing out of Africa, shipping data shows. The initial surge in imports was driven by an unprecedented short squeeze on the exchange last year, and there’s been a further up-tick in shipments since Trump’s election victory.

Whether it’s coming from Chile or the Democratic Republic of Congo, the risk for traders with copper still on the water is that tariffs are imposed swiftly, and cargoes will be slapped with duties when they arrive.

“It’s quite a risky trade because of the lack of clarity on tariffs,” said Alice Fox, an analyst at Macquarie. “It’s too late to physically move metal to Comex to take advantage of it.”

But in the silver and gold markets — where metal can reach the U.S. in a matter of hours — traders may take the opportunity down to the wire.

JPMorgan Chase & Co., the world’s top bullion dealer, will deliver gold bullion valued at more than $4 billion against futures contracts traded on CME Group’s Comex that will expire in February. The delivery notices, which total 30 million troy ounces of gold, were the second largest ever in bourse data going back to 1994. 

“The bottom line is there’s a huge arbitrage,” said Robert Gottlieb, a former precious metals trader and managing director at JPMorgan Chase & Co., the world’s top bullion dealer. “The markets are still dislocated. There are opportunities, but there are also exposures.”