Alcoa Inc. on Thursday reported a sharp drop in third-quarter profit on lower aluminum prices and unfavorable currency effects.

It was Alcoa’s first quarterly report since it announced last month it plans to split operations next year. One business will make parts for cars and planes, and the other will produce raw aluminum and its ingredients.

The New York-based aluminum producer—the first major U.S. company to report quarterly results—posted a profit of $44 million, or two cents a share, down from $149 million, or 12 cents a share, a year earlier. Revenue fell 11% to $5.57 billion, weakened by the stronger U.S. dollar and devalued Chinese yuan.

Analysts surveyed by Thomson Reuters had projected 13 cents a share on $5.65 billion in revenue.

Oversupply, exacerbated by China’s economic slowdown, has battered aluminum prices, which have fallen about 14% since the beginning of the year to less than $1,600 a metric ton on the London Metal Exchange, the world’s largest venue for metals trading.

Shares, down 30% this year, fell 5.1% to $10.45 in late trading Thursday.

Alcoa’s smelting division swung to a $59 million loss in the latest period, compared with a $245 million operating profit in the year-earlier period. The company’s average “third-party realized price,” or what it charges outside customers, fell 25% to $1,901 a metric ton. Alcoa has been cutting its high-cost smelter capacity around the world.

With the aluminum market so troubled, Alcoa has been veering off its path as a pure aluminum producer, investing in rolling sheet for auto makers and making high-tech components for airplane makers. The strategy, Chief Executive Klaus Kleinfeld told CNBC on Thursday, was to focus on “things we have in our own control.”

One potentially big opportunity is the automotive industry’s shift to lighter cars to meet fuel-efficiency standards. Alcoa has invested heavily to expand sheet capacity in plants in Iowa and Tennessee. In the latest period, automotive sales more than doubled, Alcoa said, adding these sales were expected to reach $1.8 billion in 2018. But costs crimped its global rolled-products division, with operating profit falling 10% to $62 million.

With the aerospace market buoyant, Alcoa has been expanding into high-tech titanium and nickel alloys for planes. This week, it announced a billion-dollar deal to supply Airbus Group SE with fasteners and other parts, and another supply deal, worth around $1 billion, with Lockheed Martin Corp.

Operating profit at the aerospace-related division, known as engineered products, fell 2.6% to $151 million, because of acquisition costs. Revenue in that segment rose 35% to $1.4 billion.

Alcoa has been particularly bullish about its business processing bauxite into alumina, which is used to make aluminum. On Thursday, it reported operating profit surged threefold to $212 million from a year earlier.

Alcoa is no longer as optimistic as it once was that Chinese buyers might come to the rescue of aluminum companies. It slashed its forecasts for China, including lowering its estimate for 2015 automotive-production growth to 1% to 2% from 5% to 8%.