On 30th March 2017 the market cap for Bitcoin BTC was just under $17 billion USD.  Today (29/11/2017) the market cap of BTC is over $177 billion USD.  It's the law of supply and demand. In just over 7 months, an extra $160 billion USD has come into BTC but the BTC supply hasn't increased at the same rate therefore driving up prices from $1,061USD on 30/3/2017 to today's price of $10,637.50 on 29/11/2017.