How mega-mergers are financed does not often grab the headlines. Like checking the microphones at the Oscars, it is necessary, but unglamorous. Still, financing structures could affect value creation far more than is often acknowledged.

Some studies suggest that deals paid for in cash, rather than stock, tend to generate better returns for investors in the acquiring company. A Citigroup study of US acquirers between 1990 and 2002, for example, found that cash-financed transactions outperformed the industry by 4.3 per cent in a two-year period; stock-financed deals, by contrast, underperformed by 5.2 per cent.