The latest price fluctuations revolved around concerns over a hard fork and what the implications of it might be. For now we're in the clear as far as hard fork goes. Thus price is increasing. Looking at charts of btc prices, the recent dips in price were nearly all due to uncertainty and fear over bitcoin unlimited or the latest fork. It might be fair to label it speculation but that doesn't mean there aren't reasons behind price movements that can be defined.

Goldman Sachs analysts have called for btc to reach $3,900. I would guess that's the upper limit although it could go higher. It depends on how many long term btc holders decide to dump their holdings, cash out of btc and find some new investments.