Amex trouble: American Express fell 4 percent to $77.32 Friday after its financial results took a blow from the recent sharp appreciation of the U.S. dollar. Amex's revenue fell even as its profits increased 6 percent. The stronger dollar made the company's overseas earnings worth less after being converted back into U.S. currency.

Huge queue: Netflix stock rose 18 percent Thursday, to $562.05, after the company said it added 4.9 million subscribers in the first three months of the year, better than any other quarter since it started streaming video eight years ago. Shares closed the week at $571.55.

Intel upside: Investors focused on surging server sales reflected in Intel's mixed first quarter earnings Wednesday and shrugged off sluggish PC demand, sending the company's shares up more than 4 percent, to $32.83. The stock closed the week at $32.47.

Train trouble: Norfolk Southern slumped 6 percent Tuesday after forecasting disappointing first-quarter results as demand for coal shipments fell. Shares fell 6 percent to $98.46, and closed Friday at $100.65.

Wells Fargo drops: Wells Fargo on Tuesday fell 1.4 percent, to $53.84 after first-quarter earnings fell slightly from a year earlier. Gains from trading and mortgage originations were offset by lower income from other parts of the business, such as deposit service charges. Shares closed the week at $54.05.

Building deal: Builders FirstSource said Monday it's buying ProBuild, a privately held supplier of building materials, for roughly $1.6 billion, aiming to expand its geographic reach. Builders FirstSource shares soared 67 percent, to $11.58, and closed the week at $12.99.

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