In March 2016, 315 BTC disappeared from ShapeShift's hot wallet and went to an unknown Bitcoin wallet. As a pre-profit startup, this was a major blow to Shapeshift, which started taking measures to fight back right away. During the investigation, an employee was found responsible for the theft who was then immediately terminated.
Weeks later, on April 7, 2016, ShapeShift suffered yet another blow when 97 BTC, 3,600 ETH, and 1,900 LTC were stolen from the company's hot wallet which was stored on its newly resurrected cloud infrastructure. A conversation with the suspected hacker suggested that the fired employee behind the first theft was responsible.
Then, a couple of days later, 57 BTC and 2,200 ETH were stolen from the company. At this point, what ensued could be turned into a true-crime documentary on Netflix.
In case you are interested, you can go through this detailed report by the CEO of ShapeShift, Erik Voorhees.
The company was able to trace back all the thefts to the fired employee, who was then sued. Luckily, ShapeShift is one of the few crypto exchanges to survive such a massive hacking attempt and live to tell the tale.