A market downturn is a good time for buyers. Look at the tech industry. The Nasdaq, a tech-heavy index, has fallen by 30% from its peak in November and a flurry of deals are under way. Microsoft is working on the $69bn purchase of Activision Blizzard, a videogame maker. Since March, Thoma Bravo, a private-equity firm, has spent $18bn on two enterprise-software firms. Elon Musk is—perhaps—about to purchase Twitter, a social network.
The…