Internet pranksters pulled a fast one on Apple shareholders this week, proving that even the slightest hint of negative news about the highly anticipated iPhone can create a frenzy on Wall Street.

Just before 10 a.m. Wednesday, a spoof e-mail posing as an internal Apple news alert was sent to Apple employees, informing them that the release of the iPhone, a touchscreen hybrid phone-and-music player, was being delayed from June to October. It added that Leopard, the next version of the Mac operating system, would move back its launch from October to January.

11:47 a.m., Apple sent a real e-mail to employees calling the first one a fake.

But by then, the spoof news had already hit the fast-moving blogosphere. At 11:49 a.m., news of the alleged delays appeared on Engadget, a technology blog owned by AOL, which posted the news because a trustworthy source had passed along an e-mail from within Apple’s internal system, according to an update to that blog.

Seven minutes after that posting, at 11:56 a.m., a trading frenzy of Apple stock hit Wall Street, and the company’s market value plunged $2.8 billion, or 3 percent, in six minutes. Its stock plummeted from $107.89 to $104.61 by 12:02 p.m.

By day’s end, the stock had largely recovered, closing at $107.29 a share.

An Apple spokeswoman confirmed yesterday that the e-mail was fake but would not comment on whether the company was looking for the culprit. The company said the iPhone and Leopard releases remain on schedule. A spokesman for the Securities and Exchange Commission declined comment on whether the spoof’s impact on the market would warrant an investigation.