UPDATE 2-Sony shares drop 4 pct after new business plan

(Adds analyst comments, latest share price, background)

TOKYO, June 27 (Reuters) - Shares in Sony Corp (6758.T) fell 4 percent on Friday after investors focused more on unfavourable economic conditions than the company's new business plan that includes aggressive expansion in emerging markets.

Sony said on Thursday it aimed to double revenues from the fast-growing markets of Brazil, Russia, India and China to 2 trillion yen ($18.7 billion) and invest 1.8 trillion yen in key businesses and technologies as part of a three-year strategy.

"Sony's shares are not being sold because investors thought the mid-term business plans were negative. The plans are not bad," said Soichiro Monji, chief strategist in the equity management department at Daiwa SB Investments.

"Rather, the U.S. economic outlook and a stronger yen are hurting the electronics sector today, and Sony is among them."

The Japanese maker of PlayStation electronic games and Bravia flat TVs trails Samsung Electronics Co Ltd (005930.KS) in the LCD TV market, and is locked in a three-way battle with Microsoft Corp (MSFT.O) and Nintendo Co (7974.OS) in the videogame industry.

Sony shares ended the morning session down 4.0 percent at 4,860 yen, underperforming the Tokyo stock market's electrical machinery index .IELEC.T, which lost 2.5 percent.

Sony's stock had gained 2.8 percent on Thursday in a virtually flat market amid investor expectations ahead of the announcement of the business plan, which came after the market close.

In the three-year strategy, Sony aims to lift its return on equity (ROE) to 10 percent from an average of about 6 percent over the past three years.

It also aims to turn each of its three key businesses of Vaio PCs, Blu-ray disc-related products, and microchips and electronic components into operations worth one trillion yen in three years.

Sony already has four businesses that exceed the one-trillion yen mark -- TVs, games, mobile phones and digital imaging, which includes digital cameras and camcorders.

"If the company reaches its ROE target, we think a share price of 8,500 yen would not be out of reach," Goldman Sachs said in a note to clients.

(Reporting by Aiko Hayashi, Kiyoshi Takenaka; Editing by Brent Kininmont) ($1=106.82 yen)