The stock market has incredible price momentum and broad participation but the challenges are "truly increasing," widely followed strategist Jim Paulsen told CNBC on Tuesday.
In fact, he called the optimism of late "really overwhelming."
"It's so striking because we haven't had it in the entire recovery. The wall of worry was probably the cornerstone of this bull market. … That is gone," the chief investment officer at the Lethold Group said in an interview with "Power Lunch."
"That opens you up to the bear's bite," he added.
The Dow Jones industrial average broke above 26,000 for the first time on Tuesday, less than a month after hitting its record 25,000. However, stocks pulled back later in the afternoon as investors weighed the possibility of a government shutdown.