General Electric Co. said on Thursday that it had agreed to sell its advanced materials business, which includes silicones and quartz, to private equity firm Apollo Management L.P. for about $3.8 billion in cash and securities.

GE, based in Fairfield, Connecticut, said the sale includes the stakes of its joint venture partners in GE Toshiba Silicones and GE Bayer Silicones, which it had purchased and sold to Apollo.

Separately, Germany's Bayer said that it had sold its 49.9 percent stake to GE for 475 million euros ($603 million).

GE said it will have a 10 percent stake in the new company and also have $400 million in notes.

GE said it would have net proceeds from the deal of about $2 billion after the purchase of these stakes, taxes and deal expenses. It plans to use the proceeds to fund growth and restructuring in its industrial businesses.

GE expects the deal to close before the end of 2006.

It said that the advanced materials business, based in Wilton, Connecticut, supplies silicone-based products, silanes, sealants, urethane additives and adhesives; and fused quartz and ceramics materials.

Wayne Hewett, who currently leads the business, will become president and CEO of the new company.