The insurance industry's largest-ever merger that didn't happen

Aon PLC (NYSE: AON) said that it has abandoned plans for a $24 billion all-stock takeover of rival insurance brokerage Willis Towers Watson (Nasdaq: WLTW). It gave no explanation for its decision.

The big picture: The takeover would have been the insurance industry's largest-ever merger. "Brokerages, which help connect businesses looking for coverage with insurers, have been aggressively merging to diversify, boost commissions and serve customers who increasingly want to deal with fewer intermediaries," per Bloomberg.