Following can be the reasons:

1) Increasing number of alt coins : This can be a reason for sure. Earlier anyone investing in crypto has to go for bitcoins or just 3-4 more coins. Now there are hundreds of coins and people are moving their bitcoin investments to those coins. They are doing show in hope of quicker results. Thus these coins are taking share of money which would have been invested in bitcoins.

2) Google banning crypto ads: This is another recent news that is affecting the prices negatively. When this is implemented in April 2018, we will see prices dropping even more.