The year is looking a lot like the late 1990s—market bubble and all, the chief investment officer at BMO Private Bank said Friday.
Jack Ablin told CNBC's "Squawk Box" he is using the late '90s as blueprint for what is happening now: weaker commodity prices, a strong dollar, a robust U.S. economy relative to the rest of the world, and huge foreign flows coming into the market.
With those conditions in place, the U.S. market can move higher in 2015, perhaps into bubble territory, he said.
"If the price-to-sales ratio—which is around, say, 1.7, 1.8 now—gets to be over 2 times, then I would say we're in that same bubble territory we were at the tech bubble in 1999, 2000."
The rapid decline of oil prices is cause for concern because it creates imbalances in the credit markets that remain unknown, he said, noting that many deals were done when oil was at $100 a barrel. Now oil is just above $50, even before the first coupon payment, he said.
"I do think there are lingering problems we're not aware of, very similar to the late '90s," he said. "I do see that we will start to see some of the evidence of those stresses come to light this year. We just have to see how severe they are, or if we learned our lesson 20 years ago."
Another risk is that a negative surprise on the inflation front will materialize in the back half of the year, as interest rates remain low at a time when economic numbers are trending positive and consumers are starting to pick up spending, said Alison Deans, CRT Capital's chief investment officer.
"For the first time it's something I think that could be of concern, and the Fed could be a little bit behind the curve," she said on Squawk Box."
Many investors expect the Federal Reserve to allow interest rates to rise in the middle of this year. Fed tightening is what rolled over the tech bubble, and that could happen this year, especially in the event of a growth or inflation scare, Ablin said.
Consequently, 2015 could be more volatile, and investors should sit tight if they own good companies, trust their money managers, and view volatility as their friend.
"Trying to trade around and get every last penny in trading profits I always think is crazy-making and doesn't get you good returns in the long run," Deans said.
She suggested owning strong growth companies that are domestically focused. She believes the equity market should be up around 10 percent at the end of the year.