With bond yields rising in recent months, there's been a notion that investors will flee the bond market and move into stocks.
However, Vanguard's chief investment officer, Tim Buckley, isn't buying it.
"There's this false premise out there of this Great Rotation — that everyone is going to leave bond funds and go into equity funds and it's probably quite the opposite," he said in an interview with "Power Lunch" on Tuesday.
"The last thing you want to see people do is sell their bonds and buy more equities and put more risk in their portfolio," added Buckley, who helps oversee $3.8 trillion in assets under management.
In fact, he agrees with former Clinton Treasury Secretary Larry Summers, who told "Squawk Box" on Tuesday morning that he believes the market rally since Election Day is a "sugar high."
Buckley said the market was fairly valued before President-elect Donald Trump's victory, and while it has run up since then, the fundamentals haven't really changed.
"There's a lot of euphoria in the market," he said, noting that people are excited about the prospect of infrastructure spending, cutting tax rates and the possibility of repatriating corporate profits.
"It's easy to speculate about those things but we don't know policy one around them and what form they'll take, because it really matters the form that that infrastructure spending takes and what happens with those corporate profits that are repatriated," Buckley said.
He advises individual investors to stick with their plans. For example, if someone has a 60-40 split in stocks and bonds, continue to buy into the market in that proportion.
"To do anything else is to speculate and that's not investing. Investing, at the end of the day, you're looking out a 10-year period not a 10-day period."
— CNBC's Gino Siniscalchi and Matthew Belvedere contributed to this report.