Samsung Electronics and Apple remained the top semiconductor buyers in 2015, representing 17.7% of the market, according to Gartner. Samsung and Apple together consumed US$59 billion of semiconductors in 2015, an increase of US$0.8 billion from 2014.

"Samsung Electronics and Apple have topped the semiconductor consumption table for five consecutive years, but the growth of Samsung's design total available market (TAM) was lower than the total semiconductor market in 2014 and 2015," said Masatsune Yamaji, principal research analyst at Gartner. "Samsung and Lenovo, the fastest-growing companies over the last five years, decreased their design TAM in 2015 and the risk of revenue declines from the strongest customers for semiconductor chip vendors is increasing."

The top 10 companies bought US$123 billion of semiconductors to account for 36.9% of semiconductor chip vendors' worldwide revenues in 2015, Gartner indicated. This was down from 37.9% in 2014, which was worse than the semiconductor industry's global total decrease of 1.9%.

The market decline happened partly because HP spun off its enterprise business, which bumped Toshiba from the top 10, Gartner said. Toshiba's design TAM in 2015 was US$4.6 billion, so the top 10 companies in 2014 (including HP, Hewlett Packard Enterprise and Toshiba) represented US$127.6 billion of semiconductors in 2015 on a design TAM basis, to account for 38.2% of semiconductor chip vendors' worldwide revenue.

As the growth of the personal electronic device market continues to slow, the risk of revenue declines from the strongest customers for semiconductor chip vendors is increasing, Gartner noted. Many semiconductor chip vendors, especially general-purpose chip vendors, are trying to reduce the dependency on a limited number of extremely large customers, such as Samsung Electronics, Apple and Lenovo, and are making an effort to diversify their sales targets to the fragmented long-tail small customers, so as to stabilize their business growth with a mass-marketing approach.