Shares of Hewlett Packard Enterprise fell 6% yesterday after chief executive Meg Whitman's decision to step down from the role took Wall Street by surprise. 

Whitman, one the most high-profile executives in the US, said she would quit as CEO in February and hand over the reins to company veteran Antonio Neri. 

After reports surfaced that she was being considered for the top job at Uber, Whitman reinforced her dedication to the role in July by saying that she was fully committed to HPE and planned to remain CEO. 

"We have a lot of work still to do at HPE and I am not going anywhere. Uber's CEO will not be Meg Whitman," she had tweeted. 

Whitman told CNBC yesterday that talks with Uber had not been a factor in her decision to leave HPE "at all." ‍ 

But her move caught analysts off guard. HPE is in the middle of a restructuring to cut costs, invest in research and focus on high-margin businesses. 

Its mainstay server business has been struggling as customers increasingly buy non-branded, assembled servers that are much cheaper.

The restructuring, which was announced last month and called HPE Next, was supposed to be led by Neri - a computer engineer who has spent more than two decades with the company and is HPE's current president. 

Neri's appointment is not a surprise given his increased visibility in recent months, Morgan Stanley said. 

Neri began his career in Hewlett Packard as a customer service engineer in the EMEA call centre. 

He previously led HP's technology services business and then its server and networking businesses, before taking over the whole Enterprise Group in 2015.

Since its split from Hewlett-Packard in late 2015, HPE has spent billions buying companies providing cloud software and data storage to better position itself to serve customers who are moving their operations to the cloud.