Copper prices firmed on Wednesday as investors factored in expectations of the first interest rate cut from the U.S. Federal Reserve in more than four years.

Fed rate cuts would help to boost economic activity and demand while also weighing on the U.S currency, making dollar-priced metals cheaper for holders of other currencies.

Three-month copper on the London Metal Exchange was up 0.4% at $9,064 a metric ton by 1428 GMT. Gains were pared in the afternoon by the release of U.S. inflation data showing a 0.2% rise in the consumer price index last month.

The inflation data should allow the Fed to cut interest rates next week but it is likely to dissuade the central bank from making steep cuts.

Base metals and gold are likely to remain buoyed until the rate decision on Sept. 18, said Tom Price, head of commodities strategy at Panmure Liberum.

The market expects the U.S. central bank to trim rates by 25 basis points at each of the three remaining policy meetings in 2024, a Reuters poll of economists showed on Wednesday.

"Copper will remain bound in the range of high $8,000s to mid-$9,000s unless we see a very bearish economic indicator from China," Price said.

Demand from China, the world's biggest copper buyer, slowed in August. It imported 415,000 tons of copper last month, down 12.3% from a year earlier, customs data showed on Tuesday.

Sentiment on the commodities outlook in China has been battered by a deepening sell-off in the stock market, Australian bank ANZ analysts said in a note after China's equities market slid to its lowest in seven months.

In other metals, LME nickel added 1.6% to $15,985 a ton, lead climbed 1.5% to $1,985, aluminium rose 1% to $2,362, tin was up 1% at $30,845 and zinc advanced 1.1% to $2,742.

(Reporting by Julian Luk in London Editing by Emelia Sithole-Matarise and David Goodman)