RBS Royal Bank of Scotland Group PLC

David Einhorn's Greenlight Capital Inc. bought stakes in ON Semiconductor Corp. and Interpublic Group of Cos. during the third quarter, according to a filing Friday.

Greenlight has eliminated its stake in Computer Sciences Corp.

The firm holds 15 million shares of ON Semiconductor and 2.4 million shares of Interpublic shares.

Greenlight also disclosed that it owned an 8 million shares of Citizens Financial Group Inc., the regional lender that held its initial public offering in September.

Investors who manage more than $100 million are required to disclose most securities holdings within a month and a half of the end of a quarter. The filings give the public a relatively fresh look at the portfolios of well-known investors.

Subscribe to WSJ: http://online.wsj.com?mod=djnwires