One of the most important factors is the relationship between supply and demand. In the last few months, there has been no big money to enter the market, so it is clear that the market has been falling.
Yes the demand and supply affects also the value of bitcoin. We may add the fuds and false news really affects the falling of bitcoin price. However, during this falling of price we may opt to buy and hold long term.
Many of things are there that can affect the value of bitcoin some of them are the demand and supply of bitcoin and yes news factor also effects the price of bitcoin, when ever more people sell bitcoin at panic it makes the price low and when a lot of people buy bitcoin it makes the price high, same as when some bad news come so those who are not determined sells at panic so price get down but those who have fine determination buy at even this situation cant discourage them.