BERLIN: British telecoms testing company Spirent Communications Plc said Chief Executive Bill Burns would step down immediately, and Chief Financial Officer Eric Hutchinson would take charge, sending its shares up as much as 5.8 percent.
Spirent did not comment further on Burns' exit from the company, where he was at the helm since 2008.
Shares in the Crawley, UK-based Company were up 4.8 percent at 134.7 pence at 0858 GMT on the London Stock Exchange.
The stock was the largest percentage gainer on the mid-cap FTSE 250 index.
"The change is unexpected and appears to be a consequence of the disappointing performance of the business over the past year, where Spirent has faced challenges in its core markets and missed some opportunities to benefit from stronger adjacent markets like security testing," Numis Securties analyst Nick James said in a note.
The company has been struggling over the past few quarters and reported a 72 percent drop in first-half profit last month due to lower orders and a weak performance at its network and applications unit.
"The timing of this departure suggests that perhaps we are not going to see a turnaround this year," Jefferies and Co analyst Lee Simpson told Reuters.
Spirent, which tests ethernet networks and 3G and 4G wireless networks and devices, said in a statement on Tuesday that it would begin the search for a new CEO in due course.
"They have got an excellent possible CEO in a lady called Sue Swenson, who is already on the board," Panmure Gordon analyst George O' Connor told Reuters.
Sue Swenson is a independent non-executive director on Spirent's board and has served as President and CEO of Sage Software Inc and mobile service provider Cellular One in the past.
However, Numis's James said it is likely that such an appointment could take a year or two. (Reuters)