The global smartphone market contracted by 8% to its lowest third-quarter level in a decade on subdued demand for major brands including Apple and Samsung in most developed markets, according to data from Counterpoint Research.

The data, shared exclusively with Reuters, showed that the share of the top five brands, which also include Chinese firms Xiaomi, Oppo and Vivo, had fallen to a three-year low.

The report fans fears that the market's ongoing slump could sap upcoming earnings at companies like Apple, whose shipments declined by 8% in the quarter. Market leader Samsung posted a 13% drop in sell-through volumes in the period.

Among those that gained market share in the quarter are Apple's Chinese rival, Huawei, which despite the strict U.S. sanctions against it, shocked the industry earlier this year with its Mate 60 Pro smartphone that uses an advanced domestically made chip.

But overall shipments rose 2% industrywide from the second quarter, raising hopes that the market could snap its more than two-year run of year-on-year declines in the last three months of the year.

Counterpoint cited the iPhone 15 lineup that went on sale in September as a factor that could help revive growth in developed markets such as the United States, Europe and Korea.

"Following a strong September, we expect the momentum to continue until the year-end beginning with full impact of iPhone 15 series," the market research firm said.

It said the festive season in India, the 11.11 sale event in China and end-of-year promotions across regions would also support the market.

So far, emerging markets have been a bright spot for smartphone sales in an otherwise dour year. In the third quarter, the Middle East and Africa were the only regions to record year-on-year growth, according to Counterpoint data.

(Reporting by Akash Sriram, Juby Babu and Aditya Soni in Bengaluru; Editing by Pooja Desai)