(ShareCast News) - The US stock market watchdog has reportedly begun investigating Boeing's accounting practices, with particular focus on its 787 Dreamliner and 747 jumbo jet programs. The Securities and Exchange Commission is probing the projections by Boeing Commercial Airplanes of the long-term profitability of the two aeroplanes, Bloomberg reported, citing people with knowledge of the matter.Bloomberg said it understood the review to be concerned with the use of program accounting, which allows Boeing to spread the up-front costs of manufacturing planes over many years but can result in potential losses being obscured.Boeing's stock price was more than 10% lower at $104.57 just after 1100 New York time.