It is a nightmare for any employer: what to do with a volatile, constantly aggrieved worker who has had angry, even frightening confrontations with fellow workers - yet has committed no crime.

The CVS Health Corporation, the parent of the CVS drugstore chain, said on Tuesday that it would resign from the U.S. Chamber of Commerce after revelations that the chamber and its foreign affiliates were undertaking a global lobbying campaign against antismoking laws.

Adopting a tactic widely used by 3G Capital, the Brazilian private investment group behind the recent merger of Heinz and Kraft Foods, a growing number of the world's largest food and packaged goods companies are asking their suppliers to give them as much as four months to pay their bills - even though they typically require payment from their own customers in 30 days.