Most experts attributed Apple's recent surge to investors' anticipation of next month's rumored iPhone 5 launch and the possibility that the Cupertino, Calif. company will also introduce a small, less-expensive iPad.

In a note to clients Thursday, Brian Marshall of ISI referenced the impending launch of the next iPhone when he said "180 Days of Enlightenment" were approaching. Marshall coined that phrase to describe the boost to Apple's business during the six months following a new iPhone introduction. (The converse in Marshall's model is dubbed "180 Days of Darkness," to portray the slackening sales as customers wait for the next model.)

"We are weeks away from the upcoming iPhone 5 launch and are about to enter what we refer to as the '180 Days of Enlightenment,'" Marshall wrote in his note.

Only weeks ago, investors and analysts worried over a dip in Apple's shares, triggered when the company revealed second quarter numbers that were lower than Wall Street had forecast. Since then, shares prices have increased more than $73, or nearly 13%. Prices have climbed 58% so far this year.

Friday's closing price of $648.11 was a record for Apple, beating the previous high of $633.68 set on April 5. It was also the first time that the company's market capitalization -- the value of all outstanding shares -- breached the $600 billion mark. Apple is the world's top company measured by market capitalization.