According to the latest report,
'Global Handset Vendor Market Share for 15 Countries in Q1 2017', published under Handset Country Share Tracker (HCST) service,
the combined market share of the biggest 4 OEM's in Brazil in Q1 2017 reached an all-time high level, signaling that
top-vendors-tilted polarization is under way.
The similar trend is happening in some other countries including
China and the US as well as the
global handset market.
The detailed handset vendor share in Brazil, China and the US can be viewed at
this HCST link.