I agree with those who believe that speculation is the most important basis of the previous substantial increase in the price of bitcoin, however I believe that this is not exclusive to the BTC. Most altcoins that are experiencing strong increases do not seem to have behind them any rationally valid justification for understanding these large increases, especially taking into account that "traditional" markets are considered successful when they obtain 10, 20 or 30% annual yield , when altcoin market has seen cases of 100,000% or more profit in a few days.