The fastest-growing major computer firm, Hewlett-Packard Co., on Friday reported a 42 percent jump in profit for its fourth quarter but its stock fell from investor resentment over the price for such growth - a lower profit margin.

The company’s profit of $678 million exceeded consensus forecasts on Wall Street. Much of its growth came from personal computers, which have a lower profit margin than other computers. By contrast, profit was up 66 percent in the May-July quarter over a strong performance in that period a year ago.

Lewis E. Platt, the company’s chairman and chief executive officer, expressed satisfaction with the latest results but also said margin pressures will continue.

Hewlett-Packard’s profit amounted to $1.29 per share in the three months that ended Oct. 31. It earned $476 million, or 92 cents per share, in the same period a year ago.

Revenue was $9.05 billion, up 29 percent from $7 billion a year ago.