Stocks that moved substantially or traded heavily Tuesday:
Macy's Inc., up 95 cents to $28.40
The department store reported better sales over the holidays, a positive sign for it and other retailers.
Comcast Corp., down $2.92 to $36.66
The cable company offered to buy British broadcaster Sky for $29.5 billion.
Akorn Inc., down $11.63 to $18.65
The generic drugmaker's stock fell on reports that German health care company Fresenius will end an agreement to buy it.
Nutrisystem Inc., down $8.60 to $31.30
The weight loss company's forecasts for 2018 fell far short of analyst projections.
Tenet Healthcare Corp., up $1.70 to $20.77
The hospital operator had a better-than-expected fourth quarter.
Fitbit Inc., down 68 cents to $4.86
The fitness device maker had a weak fourth quarter and is revenue forecast disappointed investors.
Microchip Technology Inc., up $2.17 to $88.55
The Wall Street Journal reported that the chipmaker plans to offer $7.5 billion to buy Microsemi Corp.
AutoZone Inc., down $81.43 to $654.47
The auto parts retailer reported a smaller-than-expected profit and said it will sell two businesses.