Shares of the US-based consumer electronics giant Apple crossed the $500 barrier for the first time on Monday. The new record was the result of a two-week gain triggered by record profits and revenues.

The company's value was put at $460 billion (347 billion euros). This makes it worth more than the combined value of rivals Microsoft and Google.

Apple surpassed Exxon-Mobil as the hitherto most valuable company on US stock markets, but analysts said Apple remained undervalued, compared to the size of its earnings.

According to the latest earnings report, Apple posted a record profit of $13 billion in the final quarter of 2011 when it was able to sell 37 million iPhones, 15 million iPads and five million Mac computers.

Investigations ahead

Also on Monday, Apple announced that independent inspectors from the Fair Labor Association (FLA) had started looking at working conditions in Chinese factories where the firm's iPads and iPhones are assembled.

The FLA team began inspections at Foxconn City in Shenzen which employs and houses hundreds of thousands of workers. Conditions had recently been the focus of criticism in a report by the New York Times.

The FLA plans to interview thousands of employees and will publicize its findings and recommendations next month.

Apple pledged full cooperation. It's the first technology company to have joined the Fair Labor Association, which focuses on improving job practices.

hg/mll (AP, dpa)