NEW YORK — Apple shares fell only slightly on Wall Street on Thursday as investors digested the stunning announcement of the resignation of the company's co-founder and visionary Steve Jobs.

Shares in the Cupertino, California-based gadget-maker shed 0.65 percent to close at $373.72 after having dropped as much as 5.3 percent in after-hours trading overnight following the announcement.

Jobs, who underwent an operation for pancreatic cancer in 2004 and a liver transplant in 2009, stepped down as Apple's chief executive on Wednesday and was replaced by chief operating officer Tim Cook.

Jobs will become chairman of the board of directors but his departure raises questions over the company's ability to build on such hit products as the Macintosh computer, the iPod, iPhone and most recently the iPad tablet.

Cook, in a message to Apple employees on Thursday, pledged to stick to the winning ways of his mentor Jobs.

"I want you to be confident that Apple is not going to change," Cook said. "Steve built a company and culture that is unlike any other in the world and we are going to stay true to that -- it is in our DNA."

Wall Street analysts noted on Thursday that Jobs has been ailing for years and said his resignation -- while stunning -- was not completely unexpected.

They unanimously expressed confidence in Apple's short-term prospects but some expressed concern about the company's long-term future without Jobs at the helm.

"Similar to the departure of Henry Ford, Walt Disney -- unique creative forces whose companies carried on for years -- Apple without Steve will go on," RBC Capital Markets analysts said. "However, it's hard to believe Apple won't be different.

"Steve was involved in every detail of product, marketing, execution, deal-making and had the vision and gravitas to bet on disruptive innovations," they said.

Barclays Capital and other analysts praised the managerial qualities of Jobs's hand-picked successor, Cook, who has replaced the Apple co-founder previously when he went on extended medical leaves due to illness.

"While we do not believe that Steve Jobs is replaceable, it is worth noting that Tim Cook is a proven executive who can handle the pressure and knows how to run the inner workings of Apple in Jobs' shadow," Barclays Capital said.

"Cook managed the company through the 2009 recession, competitive threats in smartphones, and several product transitions in Jobs? 2009 and 2011 leaves of absence," Morgan Stanley said.

"Given his track record, we see little execution risk over the next 12-24 months."

The longer-term prospects are not so clear, analysts said.

"We believe that Steve Jobs has had a unique and powerful imprint on Apple that is irreplaceable by anyone, and that longer term (more than two years out), his full time absence could undermine the performance of the company," said Bernstein Research's Toni Sacconaghi.

"We believe that it is hard to imagine a replacement for Jobs' vision, his unparalleled and charismatic marketing leadership and his ability to drive the company to exacting standards and products."