I think the saying about them being able to stay irrational far longer than you or I can remain solvent applies here in spades!
The Kingdom is very publicly trying to diversify away from oil. They're using the money from the IPO to invest in massive solar farms, among other things, which should tell the rest of us something.
It does raise a few questions. Aramco makes around $100 billion a year in profits at a net margin of >30%, and that's with today's relatively low oil prices. The IPO is supposed to raise $25 billion, or one quarter's net income. It's a bit weird to going through all the hassle and international scrutiny of an IPO to sell off part what amounts to a free money machine. If I had to guess, I'd say Saudi Arabia's overall financial situation is more precarious than most assume or recognize.
In 2016 is was 13.3B in annual profit, so it's pretty volatile, as one would expect. And keep in mind they're only selling 1.5% of the company. If you look at the politics inside the Kingdom there's a lot of signaling and other stuff going on that's probably driving this. That said, it's the opposite of an open, transparent country or market so while I don't doubt it's ability to defy gravity for a long time and so won't short it I certainly wouldn't be buying it.