Here are the companies known to be conducting investigations of possibly fraudulent stock trading based on advance leaks of Business Week magazine articles and any actions they have taken involving employees: _McGraw-Hill Inc., New York, publisher of Business Week: no employee dismissals or suspensions. _R.R. Donnelley & Sons Co., Chicago, printer of Business Week: one employee dismissed at Old Saybrook, Conn., plant and one employee suspended at Torrance, Calif., plant. _Merrill Lynch & Co., New York, investment firm: one broker dismissed in New London, Conn., office. _Prudential-Bache Securities Inc., New York, investment firm: one broker dismissed in Anaheim, Calif., office. _Advest Inc., Hartford, Conn., investment firm: one broker suspended in New London, Conn., office. _Shearson Lehman Hutton Inc., New York, investment firm: disclosure that three former brokers in Hartford, Conn., office of E.F. Hutton Group Inc. may have traded on leaked articles before Hutton was acquired. _PaineWebber Inc., New York, investment firm: disclosure that it had hired at least two of the former Hutton brokers. _Smith Barney, Harris Upham & Co., New York, investment firm: no action against employees. _Integrated Resources Inc., New York, financial services firm: no action against employees. _Quick & Reilly Group Inc., New York, discount brokerage: no action against employees. _Charles Schwab & Co., San Francisco, discount brokerage: no action against employees.