>How can every coin dip at the same time? The prices of most coins are controlled by a handful of whales. They react to peer-pressure. If others coins go up and theirs don't, their concern is that those other coins will attract more investment money from the little guy. They also have to bring them down in price on a regular basis to weed out the weak hands that sell as soon as the prices dip. Those 'weak hands' can get in the way of the whale's profit.