Costly: Wholesale club operator Costco gave up 5.5 percent to $218.82 Friday after it said it discovered technology problems related to its financial reporting processes. Costco said it is investigating, but hasn't found any problems with its past earnings reports so far.

Book sale?: Barnes & Noble climbed 23.6 percent to $6.75 Thursday after the bookseller said it will review offers from potential buyers, including one from its founder and chairman. Barnes & Noble stock has lost almost two-thirds of its value since July 2015. Shares closed Friday at $6.95.

Getting the boot: General Electric jumped 12 percent to $12.69 Monday after ousting Chief Executive John Flannery, who was on the job about a year. GE is still down by about half over the past year. The stock closed Friday at $13.18.

Ripped stitching: Stitch Fix's revenue and active client totals fell short of Wall Street's targets, and the online subscription and personal shopping service's stock plummeted 30.7 percent $30.92 Tuesday. Shares closed Friday at $26.30.

Heavy metal: Century Aluminum fell 11.9 percent to $10.49 Wednesday after a key supplier said it is shutting down its alumina plant in Brazil, which could leave Century Aluminum short of a critical material used in making aluminum. Shares closed the week at $9.97.

GM fuels up: General Motors rose 2.8 percent to $34.23 Wednesday after Honda agreed to invest $2.75 billion in GM's autonomous vehicle business over the next 12 years. Shares closed Friday at $34.12.

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