Not economic growth. Not earnings strength. It's global central banks that are driving the U.S. stock market, portfolio manager Larry Glazer said Friday.
"That's not a healthy dynamic," he told CNBC's "Squawk Box."
Case-in-point Friday morning, China's central bank cut interest rates, the sixth such move since November. After the announcement, tech-fueled gains in U.S. stock futures accelerated.
This came on the heels of Thursday's comments from the European Central Bank, which signaled it would consider extending its massive bond-buying program well into 2016 and even beyond. The Dow Jones industrial average soared 320 points as a result.
"We cannot pretend that the monster rally we've seen in the last three weeks has been driven by improving fundamentals in the economy [or] traffic earnings," said Glazer of Boston-based Mayflower Advisors, which has $2 billion in assets under management.
"That would be drinking the consensus Kool-Aid. Clearly that's not the case," he said. "Central banks [are] driving the dialogue away from fundamentals in the economy."
The U.S. economy has been struggling to really kick into high gear, and inflation remains stubbornly below the Federal Reserve's 2 percent target. Concern about contagion from a China slowdown isn't helping.