Apple Inc's shares could rise further despite having risen 51 percent over the past one year as the company's Mac PCs, iPads and iPhones have plenty of room for growth, said brokerage Sterne Agee.

The brokerage raised its price target on the stock to $445 from $400 and said it is still a buy at the current levels.

We think the beauty with the Apple story is that the company doesn't need to win everyone over to continue its success. The company just needs to continue winning a fair share of its vast end markets, analyst Shaw Wu wrote in a note.

Wu said over the next two-four years, the company's Mac personal computer market share could potentially double to 8-10 percent, excluding the iPad business.

With the iPad, the company's market share in computing devices could approach 15-17 percent, nearly that of Hewlett-Packard Co and exceeding Dell Inc, Acer Inc, Lenovo Group Ltd and Toshiba, Wu said.

The analyst said the iPhone also has a lot of headroom for growth as its market share is about 25 percent within smart phones and only 3 percent in total mobile phones.

Stern Agee also initiated coverage of Cisco Systems and several companies within the technology hardware sector.

Separately, Jefferies said both the iPhone 5 and Apple's iOS 5, which were expected this summer, is unlikely to be available earlier than this fall as Apple incorporates new cloud-based services.

Jefferies trimmed its estimates but kept its price target of $450 and buy rating on the stock.

Shares of Apple, which has a market capitalization of about $323 billion, were down about a percent at $348.17 in morning trade on Wednesday on Nasdaq.

(Reporting by Jennifer Robin Raj; Editing by Maju Samuel, Prem Udayabhanu)