NEW YORK (AP) — Standard & Poor's said Thursday it will add Freeport-McMoRan Copper & Gold Inc. to its S&P 100 index to replace Schering-Plough Corp., after the drugmaker merges with Merck & Co. in a deal expected to be completed soon.

Priceline.com Inc. will replace Schering-Plough in the S&P 500, and MSCI Inc. will replace Priceline.com in the S&P MidCap 400, S&P said in a statement.

The date of the changes were not announced.

Stocks often rise after they are added to major indexes as they are bought by managers of investment funds that mirror the indexes.