** U.S. grocer Kroger Co's KR.N shares down 2.14% at $64.82 premarket

** Kroger CEO Rodney McMullen steps down from the role after a board investigation found that his personal conduct was inconsistent with the co's "policy on business ethics"

** Co says McMullen's conduct is not related to the company's financial performance, operations or reporting

** "Markets don't like unanswered questions, and unless Kroger moves fast to reassure them, this transition could add volatility," says Riley Beam, managing attorney at Douglas R. Beam law firm

** Updates annual adjusted EPS forecast to be slightly above high-end of prior forecast range

** KR stock had risen 6% YTD, as of last close

(Reporting by Aamir Sohail in Bengaluru)

((Aamir.Sohail@thomsonreuters.com;))