NEW YORK ( TheStreet) -- The mystery of Apple's ( AAPL) undervaluation continues. Here you have a stock selling at 10.5 times its earnings, yielding 2.78% in dividends. It had a solid 10% growth in sales, year over year, in the last quarter, and a balance sheet that's cleaner than a well-run hospital, in a market where the average price-to-earnings ratio for electronic equipment makers is 12.8, and for consumer goods companies 20.58, according to Yahoo! Finance. Investors are paying more for earnings of Whirlpool ( WHR), which has no growth, a lower yield, and lacks the cash to pay off its long-term debt. Apple, by contrast, is a cash-flow machine, with $30 billion in positive cash flow each quarter. Would you rather have Apple or Whirlpool? Investors say Whirlpool. It doesn't pay to argue. You could have argued that Apple didn't care what its stock price was, under Steve Jobs. But Tim Cook has been raising the dividend and buying back stock in great heaping handfuls. There are two answers to the mystery. One is that Apple's growth rate is slowing, as the industries it created mature. This should mean declining margins over time, and declining profits. The other is that Apple hasn't made anyone say "wow" in several years, and thus investors wonder if it's still innovative enough to keep growing.
CEO Tim Cook gets his chance to address the latter concern today at the company's Worldwide Developer Conference in San Francisco. Since this is the developers' meeting, not a press conference, expectations need to be dialed-down. He's unlikely to say "one more thing," then trot out an iWatch or Apple iTV. That's for later in the summer. Instead, Cook's expected to announce changes to the company's two main software platforms -- the OS X operating system of the Macintosh line, and the iOS software used by its devices. He will probably also trot out new Macs, since those are the machines developers use. It's iOS that is most important. The "device revolution" transformed computing from something you paid $1,000 for, and did at a desk, into something you paid less than $500 for, and walked around with. Since then, the interface game has been going every which way, from gestures made in the air to spoken interfaces, and Apple may be the only company capable of delivering clarity to this.