NEW YORK (CNNMoney.com) -- Apple Computer Inc. shares soared Thursday, a day after the company reported earnings that easily topped Wall Street expectations on improved sales of Macintosh computers and iPod media players.

Shares of Apple (up $4.46 to $78.99, Charts) rose 6 percent in afternoon trading on Nasdaq, where it was the third-biggest point gainer. Shares of rivals Microsoft (down $0.23 to $28.29, Charts) and Dell (down $1.58 to $23.12, Charts) edged lower.

Piper Jaffray's Gene Munster said in a note to clients reported by Reuters that Apple's results show its "formula is working" as the popularity of its iPods is translating into a "resurgence in the Mac platform."

"We believe in six months the halo effect will expand beyond a simple iPod-to-Mac correlation into a four-way relationship with iPod, Mac, iPhone, and iTV benefiting from each other's success," said Munster. "If this plays out, Apple's growth rate should accelerate in 2007."

Before Thursday's surge, Apple stock had risen nearly 5 percent this year, compared with an increase of more than 4 percent in the Morgan Stanley High-Tech Index, of which Apple is a constituent.

-- from staff and wire reports

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