Excluding the impact of one-time items, such as restructuring costs and costs tied to a legacy legal matter, Alcoa reported second quarter earnings of $76 million, or 7 cents a share. Analysts had been expecting earnings of 6 cents a share, according to Thomson Reuters I/B/E/S.

"It looks much better than expected. It is good to see that revenue is better than expected," said Alan Lancz, president of Alan B. Lancz & Associates, an investment advisory firm based in Toledo, Ohio. "It seems like the outlook is favourable so far."

Quarterly revenue fell 2 percent to $5.85 billion, largely because of lower aluminium prices, but revenue topped analysts' expectations of $5.83 billion.

The London three-month aluminium price fell nearly 7 percent during the quarter ended June 30 and has tumbled around 13 percent in 2013. Aluminium touched a nearly four-year low late last month of $1,758 a tonne.

Stubbornly low aluminium prices caused by a global surplus and concerns about lacklustre demand have weighed on the company's business of mining bauxite, refining it into alumina and then smelting alumina to produce aluminium. This has prompted a slew of production cuts and shutdowns from Alcoa and its rivals.

The company said its net loss in the quarter ended June 30 was $119 million, or 11 cents per share. That compares with a loss of $2 million, or break-even per share, a year earlier.

(Reporting by Euan Rocha. Editing by Andre Grenon)