Apple’s rollout of an updated Macbook notebook line Tuesday failed to wow investors who drove shares down in afternoon trading.

A gaunt-looking CEO Steve Jobs unveiled the new notebooks, which feature new one-piece glass multi-touch trackpads and instant-on LED-backlit displays.

But a forecast price reduction to $900 for the entry-level Macbook failed to materialize. Though anticipation had run high that Apple would price the entry-level Macbook at $900, the lowest-priced model, the 13-inch Macbook, came in at $999.

In an interview before the unveiling, analyst Rob Enderle said that a $900 notebook could be an essential quiver in Apple’s premium-price lineup.

“During the current economic conditions, it could be a lifesaver for the firm,” Mr. Enderle said.

The analyst questioned whether even a laptop with a $900 price point would be sufficient to compete against Windows laptops whose price continues to fall.

“Apple has sold products for the last few years for a moderate premium,” he said. ‘The question is: Will the market accept $900 as a moderate premium” over PC laptops whose price has fallen to $500.

Shares of Apple fell 2.9 percent to $107.05 less than 30 minutes before the market close.

Along with a refresh of the Macbook and Macbook Pro lines, Apple upgraded the graphics card and storage options in its 3-pound Macbook Air notebook.

In a separate announcement Tuesday, South Korean electronics giant Samsung, whose laptops have been rebadged and sold by Dell in the past, announced it would market notebook computers under its own name in the United States.

Samsung’s new lineup ranges in price from a $499 netbook with a 160-gigabyte hard drive to 13.3-inch and 14.1-inch ultra-light notebooks with solid-state memory starting at $1,599 that will compete with the Apple Air.

Mr. Enderle noted that Samsung already competes against Apple’s iPod music player.

“In the mp3 player space, it’s one of the more powerful competitors to Apple,” he said. “They’re much more aggressive on price.”