The looming threat from supercorporations like Amazon is helping spur a new wave of megadeals (AVGO,

Mergers-and-acquisitions transactions worth over $10 billion are surging back after a largely dormant first half of the year. Wall Street bankers say an improving global economy and confidence in the regulatory environment are playing a role. The looming threat of supercorporations like Amazon has many large companies evaluating whether they can be an endgame winner — and whether they need to strike a deal to get there. On Thursday, Emerson Electric upped its takeover bid for...