Price manipulation is done by using many ways.Publishing speculative news in favour of boosting bullish trend is a way.Here on the below link,we could see that news sites continuously release news that bitcoin price is to boom.If we see such moves,we should be cautious about investing otherwise we may get fooled and we might have to regret for our wrong investment.Don't let news media to decide your fortune.
https://www.reddit.com/r/Bitcoin/comments/9dimq2/headlines_two_days_ago_this_is_how_market/You would have to control a whole bunch of media outlets in order to be able to influence bitcoin's price.
It would be easier with a small market cap coin.