There's an under-the-radar trend which could push stocks further into record territory, and it appears most of Wall Street doesn't even know about it.
"I think inflation will be the big surprise," said Joseph Zidle, portfolio strategist at Richard Bernstein Advisors on CNBC's "Trading Nation" this week.
His leading indicator: A tightening labor market that is driving up wages.
"This economy is really based on consumption, so it puts more money in the hands of consumers," he said, thus giving a boost to U.S. companies selling products and services.
Zidle referred to Commerce Department data showing the number of people voluntarily leaving their jobs, relative to the amount of people getting fired.
"More and more people are quitting their jobs right now," he observed. "In the law of large numbers, the only reason why people quit their jobs in big numbers is because they have something better lined up and something that pays more."
The scenario could help drive inflation to three to four percent, a number that's considered a sweet spot for companies' profits, explains Zidle.
"If we do start to see this inflation, I think it's very good for cyclicals because they have pricing powers — your energy, materials, tech, financials, small companies. I think it's very, very good for them," he said.