* July-September premiums fall for first time in 3 quarters
* Lower premiums reflect weaker spot premiums
* Producers' initial proposals were at $123-128/T (Adds comments and details)
By Yuka Obayashi
TOKYO, June 27 (Reuters) - Japanese aluminium buyers will pay up to 8 percent less in premiums in the July to September quarter after a fall in spot premiums, five sources directly involved in quarterly pricing talks said.
The Japanese aluminium premium PREM-ALUM-JP was set at $118 to $119 per tonne for metal to be shipped in the third quarter, down 7 percent to 8 percent from $128 per tonne in the previous quarter, the sources said.
Japan is Asia's biggest importer of aluminium and the premium over the London Metal Exchange (LME) cash price that its buyers agree to pay each quarter for primary metal shipments sets the benchmark for the region.
The latest agreement follows two quarters of rising premiums, up 35 percent in Q2 and 27 percent in Q1.
"We have settled the deals at $118 and $119 a tonne with all of the producers whom we buy the metal from," a source at an end-user said. He declined to be named due to the sensitivity of the talks.
A source at another fabricator said all the deals were signed at $118 a tonne while another source at an end-user said his company has agreed with all of the suppliers to pay $119 a tonne.
A source at a producer confirmed all the deals had been settled by early last week.
The quarterly pricing negotiations began last month between Japanese buyers and global producers, including Rio Tinto , South32, Alcoa Corp and Rusal , with initial offers at $123-128 a tonne.
Buyers countered at around $110 to $115 a tonne due to lower spot premiums in Asia and the United States, but some signed at $119 early this month.
"If the $119 deals were not so quickly signed early this month, we could have sought much lower levels," one source said, pointing to recent spot deals hovering at around $100 to $105 a tonne in Japan and even lower in elsewhere in Asia.
Reporting by Yuka Obayashi; Editing by Richard Pullin