Japanese aluminium buyer secures lower $380 premium in Q2 -source

(Adds comment, background on talks and supply)

By Yuka Obayashi

TOKYO, March 5 (Reuters) - A major Japanese aluminium buyer has agreed to pay a producer premium of $380 per tonne for metal to be shipped in the April-June period, down from the previous quarter, a buyer source directly involved in the quarterly pricing talks said.

The deal would mark an 11 percent drop from a record $425 per tonne (PREM-ALUM-JP) in January-March and is the first fall in six quarters, as regional supply climbs.

Japan is Asia's biggest importer of aluminium and the premiums for primary metal shipments it agrees to pay each quarter over the London Metal Exchange (LME) cash price set the benchmark for the region.

The buyer struck the deal earlier this week when a producer lowered its offer from an initial proposal placed last week, the source, who declined to be named, told Reuters.

"We've made the deal with one producer, but we are still negotiating with others," he said, adding the negotiations had advanced more quickly than in the previous round when talks had dragged on for nearly two months.

"Inventories are high and spot premiums are down. Producers apparently understand that," he said.

Aluminium stocks held at three major Japanese ports climbed for a tenth month to hit a record high at the end of January, as robust imports met tepid domestic demand.

Behind the higher imports are slack demand elsewhere in Asia and China's increased exports of cheaper aluminium products.

Japanese buyers have said they want to see quarterly premiums below $400 a tonne, given falling spot premiums in Asia, the United States and Europe.

The latest quarterly pricing negotiations began last week between Japanese buyers and global producers including Alcoa Inc (NYSE: AA - news) , Rio Tinto (Xetra: 855018 - news) and BHP , with initial offers ranging between $390-425 a tonne, according to three buyer sources.