The first half of 2016 was a record period for cancelled deals, new figures show.
The most high-profile withdrawal during the period was the $160bn (£124bn) Pfizer-Allergan merger, which was scuppered by US inversion rule changes.
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Dealogic figures for the six-month period show that the number of cancelled deals was down nine per cent on the first half of 2015.
But the value of the transactions, which totalled $606.4bn, made it the highest first-half on record for withdrawn deals.
This was helped by the fact that 10 of the deals were valued at $10bn or more.
The record period for withdrawn mergers and acquisitions (M&A) comes after a bumper 2015 in which more than $5 trillion worth of deals were announced.
The Pfizer-Allergan deal was one of the many deals announced in 2015, and represents the biggest withdrawn deal on record.
The next biggest deal collapse tracked by Dealogic was Honeywell’s $103bn pursuit of United Technologies. This deal fell apart in March.