Gunmakers stocks post gains on regulation news, then recede

Gunmakers get bump: Gunmakers rose in the first half of the week on reports of strong sales and the prospect of additional background checks and other regulations, which often boost demand. Smith & Wesson rose 13.4 percent Tuesday, to $26.41, closing the week at $22.63 and Sturm Ruger added 8.5 percent, to $66.60 Tuesday, closing Friday at $58.23.

Gap woes: Gap's shares dropped 14 percent Friday, to $22.91 after the retailer said its sales slumped more than expected in December.

Chipotle hit again: Chipotle Mexican Grill stock dropped 5 percent, to $425.90 Wednesday after the company said it received a federal grand jury subpoena as the government looks into norovirus outbreak at a California restaurant this summer. Chipotle also disclosed that sales at restaurants open at least one year plunged 30 percent in December. The stock closed the week at $413.29.

Profit squeeze: AutoNation shares fell 12 percent, to $50.09 Wednesday after the company said that despite robust auto sales it expected to report $250 to $300 less gross profit per vehicle for the fourth quarter. Shares closed the week at $48.82.

iPhone jitters: Apple shares retreated 2 percent Wednesday, to $100.52 on latest indication of iPhone sales slowdown: Foxconn, which assembles most iPhones, said it will cut working hours over the weeklong Lunar New Year holiday. Apple shares closed the week at $96.96.

Ailing CEO: Shares of United Continental Holdings dropped 5 percent Thursday to $52.41 a day after the company's CEO underwent a heart transplant. Oscar Munoz has been on medical leave since suffering a heart attack in October. United shares closed Friday at $51.89.