By George Stahl and Drew FitzGerald

International Business Machines Corp. shares posted their biggest one-day percentage drop in eight years Friday, after a disappointing first-quarter earnings report raised doubts about the company’s growth prospects this year.

The Armonk, N.Y., company’s earnings–excluding certain exceptional costs–rose 8% in the first quarter, below the double-digit percentage increase investors have grown to expect. IBM pointed to contracts slipping from the first quarter into the second quarter, possibly because of the early Easter; a slowdown in business spending in China; and the weakening yen.