Why did $BTC experience a sharp decline?

TLDR:

Mt. Gox, who once was one of the cornerstones of bitcoin trading before going bankrupt in 2014, is repaying its customers, in July.

Mt. Gox, the failed exchange, will pump as much as 140K BTCs into the market (worth approx. $9 billion).

Some analysts argue that this sudden increase of supply is expected to negate in one shot the positive effects of ETF inflows.

It is not clear how the market would react to this on the long run though. So, let us wait and see...