Wal-Mart and Discovery Communications tumble, IBM rises

IBM agreed to buy Truven Health Analytics for $2.6 billion, expanding the health care capabilities of its Watson cognitive computing system.

Adjusted earnings and revenue at the maker of drugs, vitamins and infant formula fell short of estimates.

The operator of TV channels including TLC and Animal Planet reported disappointing results.

The fast food chain offered weak quarterly results and guidance, saying McDonald's all-day breakfast and value deals from rivals are hurting sales.