Since a scary-skinny Steve Jobs showed up last summer to launch a new iPhone, rumors about the Apple CEO's health have circulated. Now, the cancellation of his annual Macworld speech has spooked Wall Street.

Wall Street analysts estimate that Jobs, regarded as a perfectionist product visionary who has resuscitated Apple's business, adds some $20 billion to Apple's market capitalization. Apple's stock price, down 5 percent in after-hours trading, is expressing fears that genteel reporters can't: Could an ever-worsening illness have led Jobs to cancel his annual Macworld keynote?

Jobs underwent major surgery in 2004 to treat pancreatic cancer. Since then, he's believed to have suffered complications which led to his gaunt appearance — an illness Apple's top flack, Katie Cotton, brazenly lied about.

Apple's official story: Trade shows are a boring, outdated form of marketing, and Apple has better ways to reach consumers. But Jobs made Macworld anything but boring through his theatrical unveilings. They caused such a frenzy that bloggers made an art of reporting on his every word in real time.

I don't expect Apple to comment on Jobs's health. He has made it clear he thinks it's nobody's business, calling New York Times columnist Joe Nocera a "slime bucket" for daring to ask. The stock market is giving voice to an impolitic concern: What will Apple look like without Steve Jobs?