* CEO to step down for personal reasons
* Will work with board to ensure smooth transition
* Shares fall as much as 15 percent (Adds analyst comment, share price, details on trading)
By Ben Deighton
LONDON, Sept 9 (Reuters) - British software group Micro Focus International announced on Wednesday the surprise resignation of its chief executive, sending its shares down by as much as 15 percent.
The company, which develops software for businesses, said its chief executive Stephen Kelly is stepping down for personal reasons, but would work with the board to ensure a smooth transition.
Analyst Tintin Stormont at Singer Capital Markets said the shares were down because Kelly had led the company through an "excellent" turnaround.
"Even if the company is more than one person, it's unsurprising that the market has reacted negatively," she said.
Stormont added that the market would be unsettled as Kelly had stepped down before the full integration of the company's recent acquisitions, Borland and assets from Compuware.
Micro Focus also said in a statement on Wednesday that trading had been in line with its expectations since its last management statement on August 12.
At 0844 GMT shares in Micro Focus were down 11 percent to 344 pence, having earlier been as low as 327 pence. (Editing by Clara Ferreira-Marques and Jon Loades-Carter)