So how does Vanguard Group founder Jack Bogle really feel about bitcoin?

“Avoid  bitcoin like the plague,” he said recently during a presentation at the Council on Foreign Relations. “Did I make myself clear?” he added.

The legendary 88-year-old investor is warning investors to stay clear of the digital currency.

His explanation? Bitcoin is too speculative. Unlike traditional stocks, he says there is no underlying rate of return and there’s nothing supporting it except for the hope you get more than you paid for it.

Bogle joins other bitcoin boo-birds like JP Morgan CEO Jamie Dimon who says “You can’t have a business where people can invent currency out of thin air and think that people buying it are really smart.”

Of course Bogle, Dimon and other Wall Street investors are hardly objective observers with their entire business tied up in their own traditional stocks, bonds, hedge funds and related investments.

Earlier today, bitcoin reached new record levels above $11,000.

You can catch Bogle’s comments at CNBC.com.

Photo of Jack Bogle courtesy CNBC