By (at least) one definition, the price action alone qualifies Bitcoin as a bubble: https://www.marketwatch.com/story/the-chance-of-a-bitcoin-crash-is-greater-

By (at least) one definition, the price action alone qualifies Bitcoin as a bubble: https://www.marketwatch.com/story/the-chance-of-a-bitcoin-crash-is-greater-than-80-2017-11-27 https://www.marketwatch.com/story/the-chance-of-a-bitcoin-cr... To that I would add a question: what's the fundamental value of Bitcoin? If you can't come up with a sensible way to calculate that, you have a price unmoored from fundamentals, which is characteristic of bubbles.