Bernstein also said bull markets are characterized by "fear and indecision" and that the signs of a bear market — including overvaluation and over enthusiasm for stocks — are not yet present, even as the markets flirt with new all-time highs.
Retail investors, meanwhile, are nibbling at equities again. But Bernstein noted Wall Street strategists are recommending their lowest allocation to stocks in the past 30 years.
Not all strategists, though, share Bernstein's expectations that the bull market will continue its run.
Byron Wein told CNBC this week he expects the S&P 500 to end the year where it started. "Eventually corporate fundamentals will take over, and I think they're going to be disappointing," said Wein of Blackstone Advisory Partners. (Read more: Dow 15,000 by Year End, Says Professor Siegel)
US Industrial Renaissance
But Bernstein sees opportunities including investing in American manufacturing, as the markets march higher.
The American industrial renaissance is the "best theme anywhere in the world," Bernstein said. He conceded that U.S. manufacturing won't return to its heyday of the 1950s and 1960s. But the sector is thriving as energy and labor costs become more competitive.
This theme was echoed by CEOs at the World Economic Forum in Davos, Switzerland this month. Cheap energy is the "bull case for the world," Dow Chemical CEO Andrew Liveris told CNBC last week. (Read more: Cheap Energy Luring Manufacturing Back to the US)