NEW YORK -- Stocks that traded heavily or had substantial price changes Monday.

       Hasbro Inc., down $1.46 to $88.54.

       The toy and entertainment company announced that CEO Brian D. Goldner is taking a medical leave of absence.

       Aspen Technology Inc., up $17.45 to $159.

       Emerson Electric entered a merger deal with the software maker.

       Hess Corp., up 70 cents to $89.85.

       Oil prices rose and helped lift energy stocks.

       Freeport-McMoRan Inc., up $1.10 to $35.23.

       Rising copper prices helped the mining company gain ground.

       KKR & Co., down 8 cents to $65.43.

       The private investment firm's co-founders Henry Kravis and George Roberts are stepping down from their posts as co-CEOs.

       CF Industries Holdings Inc., up $1.08 to $62.14.

       The supplier of hydrogen and nitrogen products said its Billingham Complex in the U.K. will continue to operate through at least January.

       Ameren Corp., down 87 cents to $81.27.

       The electric and gas utility announced a CEO change effective next year.

       Southwest Airlines Co., down $2.25 to $51.67.

       The airline cancelled hundreds of flights over the weekend, blaming its woes on air traffic control issues and weather.