WASHINGTON (MarketWatch) - U.S. real gross domestic product for the second quarter rose at a 4.2% annualized rate, unrevised from the earlier estimate, the Commerce Department said Thursday. Economists surveyed by MarketWatch expected second-quarter growth to be revised up to a 4.3% rate. A downward adjustment to private inventory investment was offset by small upward revisions to many other components. The boom in second quarter growth was led by consumer spending, exports and federal and state government spending. Consumer spending rose 3.8% in the second quarter, unrevised from prior estimates.