Donald Trump wants to slap tariffs on China — and maybe Japan. He’d build a wall with Mexico. He promises a more pugnacious American posture in the world, and probably a lot more unilateralism.

Bernie Sanders wants to jack up the federal minimum wage, tax short-term stock market trading, and probably raise other taxes and regulations as well.

Both men are rising in the polls.

And as they’re going up, the stock market is going down.

Surprised? Don’t be.

Stock markets hate three things in this world. The first is anyone who dissents from the orthodoxy of MBA economics. The second is anyone they can’t control. The third is uncertainty.

“ In a worst-case scenario (for investors, at any rate), voters will pick one or two heterodox outsiders who will threaten to turn everything upside down. ”

And both Trump and Sanders are offering all three. We’re talking Wall Street Nightmare Bingo.

It may be no coincidence that the Dow Jones Industrial Average tanked on Friday, the day after another Republican debate. Trump confirmed his commanding lead in the race, while Jeb Bush went under for the third and, surely, final time.

Yes, of course, there are lots of reasons why stock markets are down so far this year. People are worried about the slowing Chinese economy. They’re worried about falling oil prices, rising interest rates and the dangers of overpriced stocks.

But as a money manager explained to me over lunch this week, he and his clients are also focusing now on a fifth worry: politics.

Even in Wall Street’s best-case scenario, the parties will only pick establishment candidates after months of bruising primary battles.

In a worst-case scenario (for investors, at any rate): They’ll pick one or two heterodox outsiders who will threaten to turn everything upside down.

The political establishment — in places like New York, Washington and Los Angeles — has been waiting for months for the Trump movement to flame out of its own accord. In the past few weeks they have finally woken up to the shock that this may not happen. Voting begins in Iowa and New Hampshire in a few months.

In the RealClearPolitics average of recent polls, Trump leads his nearest rival, Texas Sen. Ted Cruz, by nearly two to one, 35% to 19%, while Florida Sen. Marco Rubio trailed a distant third at 12%. Neither Trump nor Cruz is an establishment candidate, and Rubio is at best an up-and-coming one. The establishment’s preferred candidate, Bush, is running way back in the single digits.

Trump is now the favorite for the GOP. Ladbrokes, the world’s largest bookmaker, now gives him a 36% chance in a crowded field, just ahead of Rubio (at about 33%). Bush is way back at 10 to 1.

Cruz and Trump spar over ‘birther’ issue

Meanwhile, Hillary Clinton has seen her national poll lead over “independent socialist” rival Sanders halve since Christmas. According to the RealClearPolitics average of other polls, it’s down to less than 10%. Polls suggest she will lose New Hampshire and may face a close call in Iowa.

It’s tempting to think that Wall Street would like the idea of a President Trump. He is, after all, a businessman.

But his pugnacious economic policies would be a dramatic challenge to the Wall Street economic consensus that has ruled U.S. politics since at least the 1980s. In many ways, his proposals are even more outside the economic orthodoxy taught at business schools than Sanders’. (For instance, in modern orthodoxy all tariffs are anathema. Few today understand how tariffs helped transform America’s economy in the Victorian era.)

Sanders remains a very long shot for his party’s nomination. He’ll probably win New Hampshire and may even win Iowa, but the betting is still that, in due course, the Democrats will coalesce behind Clinton. Yet the process may be painful and take a long time. And a Sanders nomination can’t be ruled out. Ladbrokes, the London-based bookmaker, still gives him about a 20% chance.

Clinton and Bush were supposed to be strolling to their party’s nominations around now. Both are popular among Wall Streeters and the economic establishment (for want of a better term). The stock market, to put it simply, would have been happy with either candidate.

But instead we have fear of the unknown, and the risk of someone really outside the MBA mainstream. And this may cause a lot more volatility on the stock market over the next few months. Look out.