A buyback is itself a special kind of acquisition, made at prices that are typically a bargain compared with those a company must pay for an outside purchase.

Some managements do not even think of buybacks as an option. The idea of shrinking their equity base repels them. Their inclination instead is to get bigger, and this often leads them to pay rich prices for acquisitions that never earn their keep.

Approaches to determining stock values vary, but fundamentally, each company judging itself undervalued is saying that its future stream of earnings justifies a higher price than the stock market is willing to accord it.

If a company's stock is undervalued - as many managers believe theirs is - a repurchase may offer the best payoff of all.

Larry Fink, 61, tall and outgoing and passionate about his business, is the chairman, CEO, and co-founder of the largest asset-management company in the world, BlackRock.

It is the instinctive wish of most American businesspeople, even those unlikely to be directly affected, that General Motors not go bankrupt.