said late Monday that it has been contacted by the

Securities and Exchange Commission

in connection with the timing of communication with its investors and a profit warning last week.

The contact may mean an inquiry into the company's compliance with Regulation Fair Disclosure, the SEC's 2-year-old rule on dissemination of financial information, which has seen much debate but little enforcement.

Investors questioned last week how a selloff in Schering-Plough shares began three days before the company preannounced lower earnings. In a statement, the company said it believed it had complied with all laws.

Late Thursday, Schering-Plough issued a profit warning, citing a long list of ills, chief among them the upcoming patent expiration of its blockbuster antihistamine Claritin.

The warning came after three days of selling that saw the giant pharma's shares drop 17%, to a five-year low.

As it turns out, Schering-Plough CEO Richard Kogan met with representatives of

Putnam Investments

, one of the company's largest shareholders, the day before the selling started.

On Monday, shares of Schering-Plough closed up 50 cents, or 2.89%, to $17.80 in

New York Stock Exchange