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

       Merck & Co., up 99 cents to $73.72.

       The Food and Drug Administration placed a hold on the pharmaceutical company's studies for a potential HIV treatment.

       Alcoa Corp., up $2.68 to $50.46.

       The aluminum producer will join the S&P MidCap 400 on Dec. 20.

       EQT Corp., up $1.15 to $21.27.

       The natural gas company announced a $1 billion stock buyback program and reinstated its quarterly dividend.

       Purple Innovation Inc., down 65 cents to $9.15.

       The mattress company's CEO resigned and it gave investors a discouraging update for its financial forecast.

       Terminix Global Holdings, Inc., up $6.74 to $44.15.

       The pest control company is being bought by Britain’s Rentokil in a cash and stock deal.

       Fluor Corp., up 93 cents to $24.43.

       The engineering and construction company's nuclear reactor unit is going public via a deal with a blank-check company.

       Neogen Corp., up $3.29 to $43.41.

       3M's food safety business is splitting from the company and will buy the maker of medical testing kits.

       Sunrun Inc., down $6.61 to $35.50.

       The solar energy company was weighed down by news that California could cut incentives for rooftop solar panels.