Apple shares up on anticipation for next-gen model

Apple shares rose $4.71, or 2.6 percent, to finish trading at $188.16.

Apple confirmed Monday that those online stores are sold out of the iPhone, but said units may still be available at brick-and-mortar stores run by Apple and iPhone carriers such as AT&T Inc.

Apple spokeswoman Natalie Kerris declined to comment on reasons for the shortage and on Apple's plans for an update to the device, which is widely expected to be unveiled in June at Apple's Worldwide Developers Conference in San Francisco.

In a client note Monday, Piper Jaffray analyst Gene Munster reiterated his expectation that the company will launch a version of the iPhone in June that is compatible with 3G, or third-generation, networks. He said such a product could be launched at the conference.

Besides noting iPhones are unavailable at Apple's online stores in the U.S. and U.K., Munster said that checks of 11 Apple retail stores in the U.S. showed six had the product in stock.

"Given the channels are running dry of the current models (8 gigabytes and 16 gigabytes), the limited availability is one of several indications that the release of a new model is imminent," he said.

Munster rates Apple shares "Buy" with a $250 price target.

Some analysts increased price targets for Apple's stock on Monday, as well.

BMO analyst Keith Bachman raised his price target to $205 per share from $180, predicting greater iPhone sales. And American Technology Research analyst Shaw Wu raised his price target to $220 from $210 in the wake of new carrier agreements.