According to the Wall Street Journal, Mr Callahan wrote the he intends to ‘move on to new opportunities’.
Yahoo interim chief executive Ross Levinsohn wrote in an internal e-mail that Mr Callahan ‘has been a leader and a great partner to me and the entire executive team and we will miss his calm demeanour’. However, he did not provide any further reasons for the departure.
One of the most recent legal battles that Mr Callahan was involved in was Yahoo’s lawsuit against Facebook for patent infringement. Facebook has since launched a countersuit, with both companies now reportedly seeking to negotiate a settlement.