U.S. stocks start the fourth quarter near all-time high levels, with the S&P 500 up 6.1% for the year and the Nasdaq coming off its best quarter since 2013. And, yet, pretty much everyone seems miserable about the stock market.

There are three big reasons why everyone is spooked, according to Anthony Scaramucci, founder of SkyBridge Capital, a global alternative investment firm with $12.1 billion in assets:

Throw Out the Playbook: “Rates are historically low and have been for a super long time. Anybody’s who’s been in the market for 20 to 30 to 40 years looks at their historical playbook and says, ‘Okay, I’m outside of my territory… the rules are no longer applying to what I know about the market,’” says Scaramucci, who is also co-host of Wall Street Week on Fox Business.

With the 10-year Treasury yielding just 1.6%, “you can justify these multiples we’re paying for these stocks, at least for now,” he says. “But you have to worry if you get the growth and some type of inflation that is going to cut into the valuation of the stock market and certainly hit the bond market.”

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Unnatural Ingredients: “There’s an artificiality to what’s going on,” he says. “There’s really little to no growth, but because of the environment they’re in, companies can borrow at 2.5 to 3-4%; they can buy in shares, which can increase earnings and can give you, on borrowed money, a dividend increase, and that’s propping up the market.”

New Normal: “There’s little to no global economic growth,” and although the Census Bureau says median household income surged 5.2% last year, “wages haven’t even really even gotten to where there were in 2006,” Scaramucci notes. “If you don’t engage the middle class in [the] consumption cycle, there isn’t enough wealthy individuals or demand-side governmental spending that will get you the growth you’ll need.”

That’s the bad, or at least worrying news. But Scaramucci, who is on Donald Trump’s finance committee and economic policy council, believes there’s an opportunity for the next president—“he or she”—to spur reforms that will lead to “an economic boom that will lead to higher stock prices.”