LONDON (Dow Jones)--An investor group is calling for a revamp of Vodafone Group PLC's (VOD) board due to concerns about the mobile giant's strategy and track record on acquisitions. Ontario Teachers' Pension Plan, or OTPP, which holds a 0.42% stake in the world's biggest mobile-network operator, plans to vote against the re-election of non-executive Chairman John Bond and Deputy Chairman John Buchanan at its annual shareholder meeting July 27. "For at least the last five years, the company has had significant structural and strategic weaknesses, resulting in Vodafone trading at a substantial, persistent discount to its asset value," OTPP said on its website. "Having engaged with management and certain members of the board, Ontario Teachers' believes that board rejuvenation is a critical step to catalyze a corporate restructuring and a re-examination of Vodafone's long history of poor capital allocation and disastrous M&A," it said. However, OTPP will vote for the re-election of Chief Executive Vittorio Colao, who took the helm in July 2008, as he has started to improve Vodafone's operating performance and competitiveness. A Vodafone spokesman said the company doesn't comment on individual shareholders' views, but noted that it maintains "a regular and open dialogue with them." "The board's primary purpose is to deliver shareholder value and we have continued to deliver a very strong financial performance," he added. Vodafone publishes fiscal first quarter results Friday. -By Lilly Vitorovich, Dow Jones Newswires; 44-0-207 842 9290; lilly.vitorovich@dowjones.com (END) Dow Jones Newswires July 21, 2010 08:49 ET (12:49 GMT)