* Q3 premiums mark 3rd quarterly rise to highest in over 3 yrs
* Spot premiums in Japan fall below $100 -sources
* Some buyers skip Q3 term contract - sources (Adds details in 11-13 para)
By Yuka Obayashi
TOKYO, June 29 (Reuters) - Premiums for Japanese aluminium shipments for July to September were set at $132 a tonne, 2 percent higher than the current quarter on rising spot premiums in the United States and supply uncertainty caused by sanctions on Rusal 0486.HK , four sources directly involved in the pricing talks said.
Premiums were at $129 per tonne PREM-ALUM-JP for the April to June quarter, making this the third straight quarterly increase and the highest premium in more than three years. Producers' initial offers were at $159 to $160. 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 CMAL0 set the benchmark for the region.
The negotiations began last month between Japanese buyers and global producers, including Alcoa (NYSE:AA) AA.N , Rio Tinto RIO.AX , RIO.L and South32 Ltd S32.AX . sources with buyers and one at a producer said all deals were done at $132 per tonne by Friday.
"We've settled all contracts at $132 although both sides weren't so happy with the result," a source at a trading house said.
Japan's buyers had sought lower levels as local spot premiums were hovering at below $100 per tonne while suppliers had claimed that U.S. sanctions on Rusal and new import tariffs on the metal boosted U.S. spot premiums, underlining potential tightness in the global market, the source said.
Washington imposed 10 percent duties on aluminium in March aimed at kickstarting domestic output and sanctions on Rusal in April, preventing customers with U.S. exposure from buying metal from the world's second-largest producer. as U.S. premiums held at three-year highs, Japan's spot aluminium premiums nearly halved in May, driven lower by an influx of Chinese metal and bets that Rusal would avoid sanctions. LME backwardation also prompted traders to cut their long positions. divergence (on spot premiums between Asia and the United States) complicated the quarterly negotiations," another buyer source said.
But given a gap between producers' last offer of $132 and the current spot premiums, some buyers have skipped the next quarter contract, the sources said.
"We've signed a term contract for value-added products, but not for refined ingots as we can get them from the spot market at a cheaper cost," a source at a fabricator said.
Some Japanese buyers have resumed trade with Rusal, or are in the process of doing so for July to September, while others are keeping their business with the Russian firm suspended due to concerns over secondary sanctions, the sources said.