Investors are getting carried away with Apple and anything to do with the iPod, according to an industry analyst.

Phil Leigh, analyst at research firm Inside Digital Media told USA Today: "Investors are getting gold fever here."

The iPod is partly responsible for Apple's stock increasing by a massive 187 per cent in 2004. The company now holds the title of the year's Number One stock on the Standard & Poor's 500 index.

The trouble, according to the USA Today report, is that 23 per cent of Apple's revenue and most of its growth comes from the iPod, which makes some worry Apple is vulnerable if demand wanes.

But Needham analyst Charlie Wolf isn't concerned. He thinks iPod customers will soon buy matching Apple computers. "Apple is not a one-trick pony. But the market is treating it like it is," he said.

The story is different for PortalPlayer, the company that designs the computer chips inside the iPod. IPodesktop editor Francis Gaskins said: "They're in a lake where the water is rising. But, if the water stops rising, then it's over."