Five companies in big pharma’s top 20 have come through mergers in the past 10 years or so that changed them significantly. As measured by standard financial performance parameters, the processes at Takeda and Teva (and to some extent, at Allergan) seem relatively smooth and productive. Those at Pfizer and Merck don’t. But it depends on how you look at the numbers.

In contrast to the SEC’s view that public companies’ regulatory filings give investors all the information needed to make an investment decision, the discount rate used to value a company may not reflect all its risks.

Healthcare conglomerates that divorce consumer, animal health and even generics businesses from their pure-play branded pharmaceutical groups could leave a less diversified and riskier sector in uncertain times. But the advantages are apparent.