They are falling because there are a lot of peoppe that are selling their holdings i think that us the main reason of that because the price of the bitcoins will always be in accordance to the supply and demand so if the price are falling down there are one thing the demand is also falling down. There is also one thing maybe there are a country again that are banning butcoins amd of course the bitcoin holders in that country will not be in part of us they cannot use theirs anymore so that can also affect