May 13 (Bloomberg) -- Apple Inc. said marketing chief Philip Schiller will give the keynote speech at its developers’ conference in June, quashing speculation Chief Executive Officer Steve Jobs might return early from leave to unveil new products.

Apple will spotlight its new iPhone operating system and the Snow Leopard software for the Macintosh at the Worldwide Developers Conference on June 8, the Cupertino, California-based company said today on its Web site. Jobs went on medical leave in January, saying he would be out through the end of June.

Without Jobs on stage, Apple may hold off introducing new iPhones and unveil new models at a special event later in the month or in July, said Gene Munster, an analyst with Piper Jaffray & Co. Jobs also may pass the CEO role on to Chief Operating Officer Tim Cook, who has been handling day-to-day operations, Munster said.

“Jobs may return to Apple with a reduced role, possibly as chairman,” said the Minneapolis-based analyst. He advises buying Apple shares, which he doesn’t own personally. “Until then, it appears that day-to-day operations at Apple are running smoothly.”

Jobs, 54, took leave after revealing that he was seeking treatment for a “hormone imbalance” that led to weight loss last year. His health prompted Jobs to skip the Macworld Expo conference in January after 11 straight years as the keynote speaker. Schiller, a 12-year Apple veteran, filled in for Jobs at that event as well.

Apple fell $4.93, or 4 percent, to $119.49 at 4 p.m. New York time in Nasdaq Stock Market trading. The shares have advanced 40 percent this year.

New-Product Venue

The developers’ conference, to be held in San Francisco June 8 through June 12, has served as a venue for new products. Last year, Jobs showcased the iPhone 3G, a faster version of the handset Apple began selling in July 2007. At prior gatherings, Jobs announced Apple’s switch to Intel Corp.’s faster processors and a version of the company’s Safari Web browser that works on computers running Microsoft Corp.’s Windows software.

The WWDC, which drew a record 5,200 developers last year, has sold out, Apple says on its Web site.

Analysts have speculated that the company could unveil new phones in June, as it has done in each of the past two years. Apple currently sells a $199, 8-gigabyte iPhone 3G and a $299, 16-gigabyte model in the U.S.

Munster is predicting Apple will add two versions: a higher-priced phone that adds more memory and improves on some of the current features such as the camera, and a model tied to a less costly service plan. U.S. iPhone buyers are required to sign up for a wireless service plan with AT&T Inc.

Apple could use a lower-cost iPhone to woo price-conscious buyers in China, Munster said. Apple said last month it expects to offer the iPhone in mainland China within a year. The iPhone is available in 81 countries and Apple has sold more than 21 million units since its debut.

To contact the reporter on this story: Connie Guglielmo in San Francisco at cguglielmo1@bloomberg.net

Last Updated: May 13, 2009 16:16 EDT