Based on the recently-published report, 'Global LTE-Advanced Handset Vendor Shipments by Country : Q4 2017', published under Handset Country Share Tracker (HCST), Apple turned out to post a record-quarterly-market share in LTE-A handset segment in some of major countries including China, Japan and South Korea.

This performance is mostly attributed to the healthy performance of Apple's latest flagships, such as iPhone X, 8 and 8 Plus.

In Japan, Apple alone captured three-quarters share of LTE-A handset volume in Q4 2017.
In South Korea, Apple became the 2nd biggest LTE-A handset provider, surpassing LG with a big difference.

The in-detail LTE-A handset market status in terms of vendor shipment and share can be viewed at the below report.

Global LTE-Advanced Handset Vendor Shipments by Country : Q4 2017