* Files for an IPO of up to $250 mln for semiconductor business
* Cuts revenue forecast for semiconductor business
* Shares fall 5 pct
* Expects to sell 750-900 megawatts of solar energy systems in 2014
Sept 9 (Reuters) - SunEdison Inc cut the full-year revenue outlook for its semiconductor business amid weak demand and said it plans to spin off the unit in a $250 million initial public offering to focus on the high-margin solar power business.
Shares of the company fell as much as 5 percent as SunEdison trimmed its 2013 sales forecast for the semiconductor business by $20 million to $920-$960 million, the second time it has done so. The unit had $917.5 million in revenue in 2012.
The company, which was formerly known as MEMC Electronic Materials, follows other solar companies such as SunPower Corp and First Solar Inc in shifting its focus to developing solar farms as panel prices remain weak.
In a conference call with analysts, SunEdison officials said the company has not made a decision to completely exit the business, but the divestment of a minority stake was a first step.
RBC Capital Markets analyst Mahesh Sanganeria said keeping the two businesses separate would help with valuations. "There is not much synergy between solar and semiconductor business."
The business, which makes wafers used in chips for computers, mobile phones and cars, had revenue of $239 million in the second quarter, or about 60 percent of the company's total.
The unit, called SunEdison Semiconductor Inc (SSI), will be headed by Shaker Sadasivam, SunEdison's executive vice president in charge of the semiconductor business.
SunEdison's chief financial officer Brian Wuebbels will also be on SSI board.
SunEdison also said it now expects to sell 750-900 megawatts of solar energy systems in 2014, a number that came above above Sanganeria's expectation.
The IPO, scheduled for early 2014, will have Deutsche Bank Securities and Goldman Sachs as lead underwriters, SunEdison told the U.S Securities and Exchange Commission in a preliminary prospectus. ()
The filing did not reveal how many shares the company planned to sell or their expected price.
SunEdison Semiconductor intends to list its common stock under the symbol "WFR". The company did not disclose which exchange it would list its stock on.
The amount of money a company says it plans to raise in its first IPO filings is used to calculate registration fees. The final size of the IPO could be different.