Pittsburgh (AP) -- Shares of Alcoa Incorporated rose six percent Tuesday.
The increase came after published reports that two Australian mining companies are independently considering making bids of about $40 billion for the US aluminum producer.
They are BHP Billiton and Rio Tinto, both based in Melbourne, Australia.
Alcoa's operations include a plant employing about 2,000 in Alcoa, Tennessee.
Alcoa officials are not commenting on the report.
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