WASHINGTON (MarketWatch) - The U.S. economy grew at a faster 3.7% annual pace in the second quarter, up from the initial estimate of growth at a 2.3% clip, the Commerce Department said Thursday. Economists polled by MarketWatch predicted gross domestic product would be revised up to 3.3%, but business investment was stronger than expected. Businesses increased investment by 3.2% increase of a drop of 0.6%, with spending on structures such as office buildings rising by 3.1% instead of a drop of 1.6%. Consumer spending, the main driver of U.S. economic activity, was revised up slightly to 3.1% instead of 2.9%. There were also upward revisions to state and local government spending and inventories, which could reverse in coming quarters, economists said. Corporate profits, meanwhile, rose an estimated 2.4% in the second quarter after declining by 5.8% in the first quarter. Inflation as measured by the PCE price index was unrevised, increasing at a 2.2% annual rate after declining by a 1.9% pace in the first quarter. Excluding food and energy, core PCE rose to a 1.8% annual pace from 1% in the first three months of the year.