This Is the Week Wall Street Went Nuts Over Cryptocurrencies (bloomberg.com)
Wall Street banks that weren't already on the bitcoin bandwagon appear to be piling on, or least eyeing seats, after the cryptocurrency surged to all-time highs this week on the way to $6,000. From a report: Analysts are working to keep up with demand from clients for information. UBS and Citigroup published extensive explainers on blockchain technology, while senior executives at JPMorgan Chase warmed to the cryptocurrency during the bank's third-quarter earnings call. The digital currency has risen more than fivefold after trading at less than $1,000 as recently as December, breaking the $5,000 mark this week and already targeting the next thousand-dollar level. Throughout its rise, the cryptocurrency shrugged off tighter regulations, feuding factions and warnings from the likes of JPMorgan's Jamie Dimon of fraud and an eventual price collapse.
What is a 'Bubble'
A bubble is an economic cycle characterized by rapid escalation of asset prices followed by a contraction. It is created by a surge in asset prices unwarranted by the fundamentals of the asset M and driven by exuberant market behavior.
So in a functioning market, investors should be able to go long or short on an asset -- that is, it should be possible to assert that it will rise and to assert that it will fall (or if you're clever, buying options that assert the price will remain right where it is).
As far as I can see, a hypothetical person that wanted to bet that bitcoin would fall doesn't really have a vehicle by which to take that position.
Back in 2011, Slashdot had a post about bitcoin. I thought it sounded interesting. So, I mined some and sent some money via dwolla to tradehill to mt.gox or something crazy like that and bought some. That $300 is now worth over $250k. I don't remember there being that many hater on the thread back then. If there were, I'm glad I didn't listen to them.