Recently, I wrote about the potential risks that concentration of Bitcoin in the hands of few holders ('whales') presents and the promising avenue for trading and investment fraud that this phenomena holds (see post here: http://trueeconomics.blogspot.com/2017/12/211217-of-taxes-and-whales-bitcoins-new.html).
Now, some serious evidence that these risks have played out in the past to superficially inflate the price of bitcoins: a popular version here https://techcrunch.com/2018/01/15/researchers-finds-that-one-person-likely-drove-bitcoin-from-150-to-1000/, and technical paper on which this is based here (ungated version) http://weis2017.econinfosec.org/wp-content/uploads/sites/3/2017/05/WEIS_2017_paper_21.pdf.
Key conclusion: "The suspicious trading activity of a single actor caused the massive spike in the USD-BTC exchange rate to rise from around $150 to over $1 000 in late 2013. The fall was even more dramatic and rapid, and it has taken more than three years for Bitcoin to match the rise prompted by fraudulent transactions."
Oops... so much for 'security' of Bitcoin...