Apple posted strong earnings than expected this week.

Apple posted stronger results than expected this week. Above, a customer celebrates his purchase of the new iPad Air in New York in November. (Craig Warga / Bloomberg / November 1, 2013)

Big earnings. Big stock buyback. Big stock bump.

On Thursday, investors cheered Apple's performance by sending its stock up by as much as 8.5% in early trading. 

The stock climbed to $569.50 at one point early Thursday, up from $524.75 the previous day. 

Riding a wave of strong iPhone sales, Apple on Wednesday reported fiscal second-quarter revenue of $45.6 billion, well above analysts' consensus of $43.6 billion, and up from the $43.6 billion the company posted in the year-earlier quarter.

Apple reported profit of $10.2 billion, or $11.62 a diluted share, for the three-month period ended in March, compared with $9.5 billion, or $10.09 a share, for the same quarter a year earlier. Wall Street analysts had expected $10.22 a share. 

Operating margin was 39.3%, up from 37.5% in the same period last year.

On the shareholder program, Apple's board increased money for share repurchases to $90 billion from $60 billion. The company also announced plans for a 7-to-1 stock split.

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