* Mike Walsh to become global legal chief
* Andy Prozes to retire at end of year
* Legal, risk solutions to be run as separate units
(Adds details, background)
LONDON, Nov 23 (Reuters) - Reed Elsiever plans to split its legal and risk businesses when LexisNexis Chief Executive Andy Prozes retires at the end of the year and install U.S. legal chief Mike Walsh as global head of legal.
The company's legal business, particularly in the United States, is in focus as Reed invests in new products to help it win back market share lost to Thomson Reuters' Westlaw in a difficult market.
The Anglo-Dutch professional publisher and exhibitions operator said on Tuesday that Prozes, who will be 65 in January, would not be replaced on the company's English, Dutch or group executive boards.
Walsh, who joined LexisNexis in 2003 and has led the U.S. legal markets business since 2008, will now assume charge of a 1.7 billion pound ($2.7 billion) global operation accounting for about 28 percent of Reed Elsevier's total revenues.
Jim Peck will continue to run the risk solutions business, which includes personal data provider ChoicePoint, and which will now be run as a separate unit from legal, reporting directly to group CEO Erik Engstrom.
Reed Elsevier shares slipped 0.4 percent to 533.5 pence by 1535 GMT, broadly in line with the European media index.
(Reporting by Georgina Prodhan; Editing by Michael Shields)