The power of Bitcoin is often what people point to as its weakness - the fact that it isnt backed by any ~one~ conventional govt/issuer.
No, it's a weakness.
Any number of entities (governments, Columbian drug cartels, Russian Mafia, etc.) could have been quietly buying up bitcoins for the last six months and sitting on them. Lack of liquidity creates a seller's market so bitcoin prices skyrocket as a result. When the time is right they can dump all their coins on the market for a massive profit. The price of bitcoin will crash and they can buy back their stock at a fraction of the price just in case it ever recovers.
This trick only works if you can do it in secret (so people mistake the lack of liquidity for market confidence - nobody wants to sell!!)
Bitcoin is a perfect target for it.