There are still some question marks about whether bitcoin is in a bubble. But the speed of its price growth is already nearly unmatched. The cryptocurrency has surged 162% in very volatile trading this year amid continued demand. But as the chart below illustrates, bitcoin’s longer-term rally by as much as 1,000% was swifter than homebuilder stocks in the lead up to the housing crash. Jeffrey Kleintop, the chief global investment strategist at Charles Schwab, said that “the…"Bitcoin’s ‘bubble’ is unlike anything we’ve ever seen"