The figures are more or less the same as those announced by Canalys on 1 November; which were 83 million units and a 15% year-on-year decrease.
IDC said the decrease was due to soft demand, supply constraints imposed on Huawei by the US, and delayed launches of flagship models by both Apple and Huawei.
"The escalated US trade restrictions in August ultimately impeded Huawei's momentum in its home market," said Will Wong, research manager for Client Devices at IDC Asia/Pacific.
Despite its problems, Huawei remained the top vendor, with 35.1 million units shipped, a drop of 15.5% year-on-year.
vivo was second with 15.0 million units, a fall of 16.9% year-on-year, while its stable,ate OPPO shipped 14.1 million units, once again a drop, this time of 14.2% year-on-year.
Xiaomi with 11.0 million units (up 13.4% year-on-year) and Apple 7.0 million units (down 13.1% year-on-year) made up the top five.
IDC said China had so far shipped 117 million 5G handsets since 2019, with 49.7 million in the third quarter of 2020. Again, Huawei led the market, while OPPO and vivo remained in the second and third spots respectively.
"External factors such as political risk could spur a possible reshaping of the market as well as an opportunity for growth and expansion," said Xi Wang, research manager for Client System Research at IDC China.
"Therefore, having a contingency strategy as part of one’s business expansion initiatives will be crucial for vendors and their business partners to deal with any unfavourable changes."