There is very little genuine manufacturing left in Singapore. Back in nineties, there was big industry for trade agencies which imported random cheap stuff, and resold it to the West after stamping things with "Made in Singapore."

I assume, the big portion of manufacturing other than output of chip fabs, is the remnant from those years. Add it to that double digits of trade and services will also relate to the same activity.

And a big portion of services labelled as other and business services will relate to offshore banking.

And yeah, both countries run humongous sovereign funds, or better to say, both countries are ran by them.