* Russo quits as CFO after 4-1/2 years
* Russo to join Wilko as CFO
* Succeeded as Asda CFO by Rob McWilliam (Adds that Russo to join Wilko)
LONDON, July 3 (Reuters) - Asda, the British supermarket arm of Walmart, said Chief Financial Officer (CFO) Alex Russo would leave the business and would be succeeded by Rob McWilliam, a former finance director of the group.
Asda, which agreed in April to be taken over by rival Sainsbury's for 7.3 billion pounds ($9.6 billion), said Russo would depart at the end of the month after four and a half years in the job.
In a separate statement discount retailer Wilko said Russo would join the firm as CFO later this year.
"Alex has been discussing his desire to seek a new challenge for more than a year and we're delighted that he has found the right business opportunity that he has been looking for," said Asda chief executive Roger Burnley.
McWilliam left Asda in 2012 after 15 years in the business to lead finance and consumables for Amazon UK. In January, he started working with Asda again on a consultancy basis, advising on strategy.
"We've been looking for a CFO who combines a deep knowledge of UK grocery retail, knowledge of Asda and Walmart relationships, and the skills to support the work we have to do to successfully complete our combination with Sainsbury's," said Burnley.
Sainsbury's takeover is being probed by Britain's regulator, the Competition and Markets Authority.
Sainsbury's is due to release an update on first quarter trading on Wednesday.
($1 = 0.7585 pounds) (Reporting by James Davey Editing by Paul Sandle and Edmund Blair)