Shares of the iPad and iPhone maker eclipsed the $600 barrier for the first time on Thursday, only about a month after first topping $500.

Just a day before Apple's new iPad becomes available in stores, the stock ticked up to $600.01 at Thursday's open before selling off. The new iPad, at a starting retail price of $499, costs less than one share of stock.

Apple Inc's rally has been stunning - the stock is up 47 percent for the year and nearly 10 percent for the month.

"There is buyers' panic out there. What kind of a right-minded person would buy this after looking at an Apple chart that has been basically up in a straight line?" said James Dailey, portfolio manager at TEAM Asset Strategy Fund in Harrisburg, Pennsylvania. Dailey owns put options in Apple as a hedging tool because the stock is "too hot to short."