Dec. 29 (Bloomberg) --The potential share of London Metal Exchange copper stockpiles held by one unidentified company fell to 80 percent to 89 percent, from at least 90 percent.

The holding covers inventory already owned and contracts expiring in the next two trading days, according to the Dec. 23 data, released today. The figures are used by the LME to apply guidelines that oblige the owner to lend metal at fixed rates.

One party actually owned 50 percent to 79 percent of the stockpiles, not counting open futures positions, as of Dec. 23, according to the exchange. A dominant position holder, to whom the lending guidelines are applied, is anyone owning at least 50 percent of LME registered stockpiles. There has been a dominant owner in copper since Nov. 24.

Copper’s cash contract, for delivery in two trading days, was trading at a $50 premium to the benchmark three-month contract by 12:23 p.m. in London. That futures market structure, known as backwardation, is an indication of concern about near- term supply.

The premium is attracting additional supply to warehouses, with inventory rising for an 11th consecutive session today, LME data show. That’s the longest streak since January.