NEW YORK -- Stocks that traded heavily or had substantial price changes Friday:

       Invesco Ltd., up $1.36 to $26.25.

       The investment management company is reportedly in talks on a potential deal with State Street's asset-management business.

       Thermo Fisher Scientific Inc., up $36.36 to $596.80.

       The maker of scientific instruments and laboratory supplies gave investors an encouraging business update.

       Lincoln National Corp., up 96 cents to $67.54.

       The insurance and retirement business announced a reinsurance deal that will generate about $1.2 billion of capital.

       Diamondback Energy Inc., up $2.55 to $82.62.

       The oil and gas company announced a $2 billion stock buyback plan.

       Protagonist Therapeutics Inc., down $28.60 to $17.53.

       The biotechnology company's development program for drug candidate rusfertide was put on hold by the Food and Drug Administration.

       Schlumberger NV, down 55 cents to $28.31.

       Slumping oil prices weighed down the oilfield service company's stock, along with other energy companies.

       Enbridge Inc., down 41 cents to $39.65.

       Minnesota regulators ordered the oil and gas pipeline to pay more than $3 million for allegedly violating a state environmental law.

       Norwegian Cruise Line Holdings Ltd., up 53 cents to $25.59.

       The cruise line operator gave investors an encouraging update on bookings for its Oceania Cruises business.