Should you own these in your portfolio? I think so (my opinion - do your own research). Sure, they sit on lofty multiples. For example, Amazon sits on a trailing 75x PE ratio. Yes, it has to shoot the lights out. It has to change the world. So far, it has done exactly that.
But guess what? I also own stocks such as Walmart. An old dinosaur to many.
Investing is about constructing a portfolio. Far too often we only talk about the stocks we should buy. A handful. A proper investment portfolio has more than a handful of stocks. A good investment portfolio should survive the multiple different futures.
I truly believe "The Four" will grow more powerful and continue to change the world. I could be wrong though and my investment portfolio takes this into account. The companies of tomorrow could actually be resurgent old dinosaurs or companies that haven't been founded yet. My point is that I have exposure to all of them.
I am not trying to have the best investment portfolio. I just want one that will grow a few percentage points ahead of inflation and one that will be around in 30 years time.
I'll leave the bold calls to the "pro's"...
