This might be a noob question. Is it possible to invest company like Grab? ̣I am pretty sure it is not listed yet but I think we see alot of potential for the company?

Stay far away from Grab.

Grab is still a privately-held company, so that means that the opportunity to invest in Grab now, at a $14bn valuation as of its Series H round from Softbank, is likely not available to retail investors right now.

That said, if you knew the Grab founders when it started, and put in money as an angel investor when it was still starting up, that would have been a different story ;)