Just as investors were coming to terms with the end of a spectacular four-year boom in mergers and acquisitions, a wave of deals has been unleashed in the midst of a credit crunch, increasing hopes that more activity will follow.

This week alone there have been close to 500 new deals announced across the globe, worth a total value of more than $21bn – making it the highest global weekly figure this year to date, according to Dealogic, the financial data provider. “Corporate M&A is in surprisingly good shape. BHP/Rio Tinto’s obviously causing a lot of excitement but the level of business generally is good,” Tom Cooper, European head of M&A at UBS said.