This is a question that you should always be asking if you want to sell or buy bitcoins, especially if it is large quantities. The price of the bitcoin relies on supply and demand, that’s why the price is so susceptible to change when you compare them with currencies like the dollar or the euro.
The supply is created by the people who are selling, and it is increased by the miners. On the other hand, the demand is created when people are buying. When the bitcoin reached its peak price in 2013, it was because its popularity blew up, heavily increasing the demand.
The use of the bitcoin had a steady increase in 2015, and some say that it will keep increasing for a few years, but to counteract that, the supply also increases, and that constant fight is what fluctuates the price.
But there’s one thing to take on consideration in 2016, the halving. It is the halving of the bitcoin reward when a new block is mined, which will reduce the growth of the supply, adding to that, this could throw off a lot of miners, further reducing said growth, thus, the price should increase by a lot.
Will the price double after the halving?
Most likely not, the majority of the community knows that the halving is coming, and are prepared for it, so, is hard to say that the price will go up too much. It is almost certain that it will rise, but nobody knows for sure how much. The halving occurred in 2012, but the bitcoin wasn’t known too much back then so price barely will go up. Since there are many more people today using bitcoins, is not the same situation, we will have to see.