Summary.
In the 1970s a revolution occurred in the field of corporate strategy. A boom in mergers and acquisitions launched new professions in M&A banking, M&A law, and strategy consulting. Given an active and efficient market for corporate control, companies shifted their focus from owning the most attractive businesses to owning the businesses in which they had a competitive advantage. If an owner was not advantaged, even its fastest-growing or most profitable businesses could be sold at a premium. Conversely, when the company was competitively advantaged, keeping even its least exciting businesses made sense.