LONDON (Reuters) -Prices of tin for nearby delivery on the London Metal Exchange (LME) have soared compared with those for longer maturities due to one company holding more than half of the inventory in LME registered warehouses.
This, traders say, makes it expensive for companies that have sold large amounts - short positions - of tin to deliver against their contracts or roll them forward.
The premium or backwardation for cash tin over the three-month contract climbed to $1,300 a metric ton on Thursday, the highest since November 2021, from $440 on Monday.
Tin contracts expiring in June are priced at a premium near $1,100 a metric ton over the three-month contract, while the June over the July contract has traded at a premium of $700.
"Whether the shorts unwind their positions or roll them forward, it's going to cost," a metal trader said.
LME data published with a two day lag shows one company holding between 50% and 79% of tin warrants - documents that confer ownership of metal in LME warehouses.
Other LME data also published with a two-day day lag shows two companies holding 20%-29% of open interest - the number of outstanding contracts due to mature or be rolled over at the next settlement date - for August.
The LME does not publish names of companies with large holdings of metals or contracts.
"The LME is closely monitoring the tin market in light of the significant tightness in tin spreads," the exchange said in response to a request for comment.
Part of the problem, traders say, is low stocks of tin in LME registered warehouses, which at 2,025 metric tons are down 60% since Sept 2022.
"There's a big difference between 50% of 2,000 tons and 50% of 5,000 tons," a tin trader said, adding that the LME tin market was illiquid. "It doesn't take a lot to move prices."
"The LME’s deferred delivery mechanism and backwardation cap are currently in place to manage low stock situations such as this, which are working as intended," the LME said. "However, we remain ready to take further action where necessary."
Benchmark tin hit a near-two-month high of $27,335 a metric ton and was last up 1.9% at $27,275.
Prices have been boosted by worries about supplies in Myanmar and production cuts due to maintenance in China.