German conglomerate Siemens ( SI) late Wednesday said that it will buy U.S. software maker UGS for about $2.1 billion and assume $1.4 billion in UGS debt, published reports say. According to the Associated Press , the sellers are private-equity firms Bain Capital, Silver Lake Partners and Warburg Pincus, which acquired UGS for $2.05 billion in 2004 in what is thought of as the largest technology buyout at the time. Plano, Texas-based UGS, formerly a part of Electronic Data Systems ( EDS), makes 3D and product lifecycle management software. The deal is pending the approval of regulators in the U.S. and Europe; no date has been set for completion of the sale. Reports also said that Siemens plans an initial public offering of its automotive engineering unit, VDO. Earlier Wednesday, the German engineering group was ordered by the European Commission to pay a fine of 397million euros, or $514 million, because the company played a leadership role in a price-fixing cartel. Shares of Siemens closed the regular session up $1.77 to $100.19.