It's been a bad day for Coinbase (NASDAQ:COIN), the leader in cryptocurrency exchanges, as the stock is down in today's session. The overall decline in cryptocurrencies sent Coinbase lower, as values on the leading coins slipped to lows not seen in the last several months. Given the overall state of the last several months, that's a pretty substantial drop indeed. A slate of other developments, like one particularly large bitcoin investor moving coin off Coinbase, also contributed to the drop. The last 12 months for Coinbase stock have been highly volatile. Last September started with a slow rise, which challenged $370 per share.