A Barclays Capital analyst says Tim Cook is up to running Apple Inc. in Steve Jobs' shadow, but Jobs is still irreplaceable.

We also believe that Apple has a strong culture that can endure. The stock has already recovered from the immediate headline pressure of this release and we continue to expect sentiment to improve through next year with strong execution and new product cycles, said Ben Reitzes.

While the economy remains a concern for all companies in the sector, Reitzes expects Apple to gain substantial share in smartphone and PC-related segments as the entire company executes its strategy.

In an open letter to Apple's board Aug. 24, Jobs said the day had come when he could no longer meet his duties. He resigned as CEO and anointed COO Cook as his successor.

The board of directors named Cook the new CEO and Jobs as chairman.

Reitzes notes that in connection with Cook’s appointment as CEO, the board awarded Cook 1 million restricted stock units (worth about $384 million vesting over 10 years; 50 percent scheduled to vest on Aug. 24, 2016; 50 percent on Aug. 24, 2021, subject to Cook's continued employment with Apple).

On Jan. 17, Apple announced that Jobs was taking a medical leave of absence. Reitzes noted that this marked Jobs' second medical leave of absence in two years (he also announced a medical leave of absence on Jan. 14, 2009).

But Jobs continued as CEO and was involved in major strategic decisions for the company with Cook taking over day-to-day operations, as he did in 2004 and 2009.

Reitzes believes Cook is a very talented executive who deserves a lot of credit for key Apple attributes that are not thought of as Steve Jobs territory.

He credited Cook with spearheading Apple's successful efforts to streamline its supply chain after the tech bubble. His focus on maintaining low inventory has contributed to Apple's industry-leading cash conversion cycle as well.

Cook has also served Apple well in negotiating component prices and build plan arrangements, resulting in industry-leading margins, Reitzes said. One can assume that he has learned a lot from Jobs over the last 13 years on the innovation front.

We believe Cook shares Jobs' taste for simplicity and style -- and will try to maintain the culture Jobs has instilled. Note that Apple also has other very talented executives, including Head of Design Jonathan Ives and CFO Peter Oppenheimer, said Reitzes.

Apple stock closed Tuesday's regular trading up 0.03 percent at $389.99 on the NASDAQ, while in after-hours the stock moved down 0.41 percent.