"The company has historically been very conservative, and the repurchase plan represents a change in mentality," Ms. Ghez said.

With stock prices at record levels, aggressive repurchase plans look increasingly dicey.

In a statement, Time said it viewed the repurchase plan as "an excellent way to increase the value for shareholders."

But when big repurchase plans occur even as company insiders are dumping their own stakes, buybacks become downright perplexing.

G.M. appeared to acknowledge its financial pinch in the terms of its repurchase plan.

Quaker Oats said it would buy back up to 3.3 million shares from the 7-million-share repurchase plan.

The company linked the active trading of its stock to its repurchase plan.

The three-year repurchase plan would cost about $1.8 billion at current market prices.

Analysts said the repurchase plan reflected a feeling among Coca-Cola executives that the company's level of debt was too low.

The company, which makes Hershey's chocolate and Ronzoni pasta, plans to finance the repurchase plan with cash.