Fund managers AsianInvestor has spoken to in Dubai this week won’t be spending today enjoying a picnic in the desert. After prayers, they are going to be watching very closely the events in Saudi Arabia, where the region’s next popular protest is planned.

At this point we simply can’t predict what the outcome will be. That uncertain outcome is what could make Friday the make-or-break day.

It could all pass quietly, with a few hundred demonstrators demurely making a point, or it could go in quite the opposite direction and mushroom into a challenge to the regime.

If the former happens, it is likely to be taken as a sign by fund managers that the contagion from nearby countries has fizzled out. Markets will be buoyed.

But if things kick off in earnest, then all bets are off and the markets are likely to swoon again, because unrest in Saudi Arabia, as far as financial markets are concerned, would be of a different order of magnitude to something similar happening in a country like Egypt. As stock markets fall, the inverse reaction by the crude oil price would be simultaneous.

Stock markets in the Middle East and North Africa region have lost $116 billion in the past five weeks, wiping 11% off a total market capitalisation of $1 trillion. There has been some evidence of a rebound this week, but such a lot now hinges on today's demonstration in Riyadh.

“I’d be lying if I could give a precise outlook,” says Haissam Arabi, CEO of Gulfmena Alternative Investments, who will be diligently following Friday’s events. His fund is 3% net short at present, but he may swiftly change that exposure if the vibes from Saudi Arabia are favourable.

So much now hinges on top-down politics in the region, he adds, and the impact of unrest on the price of crude creates another angle.

“Higher oil prices mean more government spending from oil revenues," says Arabi. "That trickles down to the corporate sector, and that determines more asset-allocation decisions depending on where that money is deployed – say, into education or infrastructure.”

He’s not arguing that unrest has benefits for the Middle East because it means higher oil prices: unrest is categorically a bad thing for the region's financial community and the fabric of its society.

What Arabi is saying is that this event has multi-dimensional implications. Price-to-earnings ratios look cheap to him right now, but political events could still push stock prices lower. So, short term, he is cautious.

So, watch the news from the Gulf today, and remember: Middle Eastern markets are shut on Fridays.