TL;DR: Researchers claim to have proof that the 2013 spike to $1,000 was engineered through fraud. It's unclear how much relevance this has to today's far deeper markets. Which isn't to say there isn't fraud going on today, as even a casual glance at ICOs will show, just that it's going to be that much harder to manipulate the price.
In recent work, we show that the first time Bitcoin reached an exchange rate of more than $1,000, the meteoric rise was driven by fraud (Gandal et al. 2017). We leverage a unique and very detailed dataset to examine suspicious trading activity that occurred over a ten-month period in 2013 on Mt. Gox, the leading Bitcoin currency exchange at the time. We first quantify the extent of the suspicious/fraudulent trading activity and show that it constitutes a large fraction of trading on the days the activity occurred. We then show how this trading activity affected the exchange rates at Mt. Gox and other leading currency exchanges [at the time].
In recent work, we show that the first time Bitcoin reached an exchange rate of more than $1,000, the meteoric rise was driven by fraud (Gandal et al. 2017). We leverage a unique and very detailed dataset to examine suspicious trading activity that occurred over a ten-month period in 2013 on Mt. Gox, the leading Bitcoin currency exchange at the time. We first quantify the extent of the suspicious/fraudulent trading activity and show that it constitutes a large fraction of trading on the days the activity occurred. We then show how this trading activity affected the exchange rates at Mt. Gox and other leading currency exchanges [at the time].