Pet peeve: company market cap cannot and should not be compared to GDP of a country. The best comparable is the "Gross Value Added" GVA = delta in EBITDA + employee compensation, as outlined here by Matt Klein in FT Alphaville:
https://ftalphaville.ft.com/2015/01/28/2103622/if-apple-were...
Others have recently estimated Apple GVA to be 0.5% of US GDP and 0.15% of world GDP.