Beginning of this year I see BTC and altcoins markets are higher valued. But Since Feb of this year thats markets are falling down. Its still not yet stable and i see lot of Panic seller in this period. I want to know whats the reason for it. Please give any idea 
Most of the gains on alts are made in BTC so when bitcoin's value goes down people try to quickly sell their alts and then sell bitcoins to lock the profits in their native currency.