Read MoreM&A activity set to hit pre-crisis levels
This is due, in part, to the collapse of one big, headline-grabbing bid which was large enough to affect volumes all by itself. When big pharma company Pfizer withdrew its $122.6 billion bid for AstraZeneca, this became the second largest bid ever to be withdrawn, after mining giant BHP Billiton's $147.8 billion offer for Rio Tinto in November 2008.
The AstraZeneca/Pfizer collapse (for now) highlighted a number of reasons for the rise in withdrawn deals.
Read MoreIs M&A fever back?
"Political and regulatory aspects of big transactions are becoming more intrusive. There's a real shift on the part of boards, into thinking not just of shareholders but of other stakeholders," John van Rossen, a partner at Ernst & Young specializing in transactions, told CNBC.
The U.K. government weighing in on the Pfizer bid, and France getting involved in Alstom's future, marks a trend that is set to continue.
"In the post-crisis world, (bidding) companies are being more cautious and scrutiny has been increased," Sriram Prakash, head of M&A insights at Deloitte, told CNBC.
"Bidding companies need to be much better prepared, and clearer about what the end game is."
Read MorePfizer decides to drop AstraZeneca deal