The stock market's wild ride over the past week has been "the biggest exercise in sheer unadulterated speculation" Jack Bogle has ever seen in his more than 60 years in the business, the index mutual fund pioneer said Friday.
His advice to investors—don't do anything right now.
"It's just speculators not speculating on what they think is going to happen but what they think other speculators think is going to happen," the founder of the Vanguard Group said in an interview with CNBC's "Power Lunch."
"This speculative binge that we're seeing here … has nothing to do with the fundamentals behind the long-term value of equities in particular, which are created by the values of corporations, earnings and dividends, and reinvestment in the business."
While equity valuations are relatively high, there isn't really a better alternative, he said, especially with bonds yields only slightly higher than stock yields.
Bogle said his portfolio is conservative, made up of 50 percent stocks and 50 percent bonds, and it's only down about 1.5 percent for the year.
"That's not a time to panic," he said, noting that anyone who has a good, balanced portfolio shouldn't be off more than 2 or maybe 3 percent.
He suggests investors follow his lead.
"Do your best to keep your eye off the headlines, do your best to avoid any stock tips and certainly do your best not to do anything extreme."