Nearly three-quarters of the 70 percent of the companies in the Standard & Poor’s 500 index that have reported their fourth-quarter results so far have beat analysts’ expectations, CNNMoney.com reported.

Profits for the S&P 500 increased by 37 percent in the final three months of 2010, compared with the year-earlier period, an indication that companies are benefiting from actual boosts in demand and not just reducing costs.

“It’s nice to finally see top-line growth out of these companies again,” said Eric Marshall, director of research with Hodges Capital Management. “We’re not fully recovered yet, but this quarter showed progress.”

And though the improvement is good news for corporate executives, many of whom have been talking about plans to increase capital spending this year, other companies are concerned about the rising costs of commodities.

PepsiCo Inc. said today that it faces “a potentially difficult competitive pricing environment, particularly in beverages.”

“This is an industry-wide issue, and we know we’re not alone in experiencing margin pressures,” ConAgra Foods Inc. CEO Gary Rodkin told investors last month when the company reported its earnings.