Apple's stock price hit $500 per share for the first time on Monday, peaking at $503.83 in yet another sign that the company's fortunes continue to rise.

The stunning accomplishment came on the heels of a steep uptick that began two weeks ago when the tech giant released its stellar first-quarter earnings report, which showed that profit had more than doubled vs. last year's Q1 results, Investor's Business Daily reported. The announcement earlier this month that the iPad 3 would be revealed in March also fueled the stock's meteoric rise in recent days.

Apple Inc. (AAPL) is not the most expensive stock in the S&P 500, however, as Google Inc. (GOOG), Inc. (PCLN) and Intuitive Surgical Inc. (ISRG) all come in at more than Apple's selling price.

But Solaris Group LLC Chief Investment Officer Timothy Ghriskey told Bloomberg Monday that the stock has nowhere to go but up:

It reminds us all of the amazing transformation of Apple over the past eight years, Ghriskey said. We think the stock has higher to go, $600 is next ... It's still an inexpensive stock for a company that is executing at the very highest level and continues to innovate.

Apple Inc. and Exxon Mobil Corp. have been alternating as the world's most valuable company since last summer, the Washington Post reported, but the rally over the past two weeks has made the company the clear leader, with market capitalization of $465 billion, vs. Exxon's $400 billion.

And Ron Johnson, Apple's former retail chief and current J.C. Penney CEO, told Yahoo! Finance on Monday that Apple's best days are still in the future.

Apple is incredible at creating products that people love, Johnson said. Nobody does hardware better; nobody does software better. Nobody does retail better. And they're just getting started in places like China.

The new heights for Apple come despite the death of the company's leader, Steve Jobs, last year. Johnson told Yahoo! Finance the company will continue to innovate and excel based on the framework that Jobs built:

Steve Jobs built a team that is equally unmatched and I expect that team to really excel in the decade ahead, Johnson said.

Despite all the positives, Apple has been having some problems, specifically in dealing with criticism of its Foxconn plant in China, which has been likened to a sweatshop.

Apple announced Monday that it is asking the Fair Labor Association to conduct special voluntary audits of Apple's final assembly suppliers, including Foxconn factories in Shenzhen and Chengdu, China, Yahoo! Finance reported.