Knight Vinke Asset Management, which owns two per cent of VNU, said on Thursday it had rejected the bid and was looking to install its own choice of CEO.
Fidelity International, which owns a further 15 per cent, has said it is also unlikely to support the deal.
Because the holders of 95 per cent of VNU's shares must agree for any deal to go through, Fidelity and KVAM could yet scupper the agreement with Valcon.
M: Communications' role has been to make sure that Valcon – whose partners could break up over Fidelity and KVAM's rejection of the deal – speaks with one voice. The partners are Alpinvest, Blackstone, Carlyle, Hellman & Friedman, KKR and Thomas H Lee.
Permira and Apax Partners, two of the original members of the consortium, quit before the latest, improved offer was tabled because they felt the price was too high.
M co-founder Hugh Morrison is also trying to communicate the agreement struck by VNU's management that Valcon will not break the company up for at least 18 months. But KVAM believes that a public sale of VNU, including a disposal of its main divisions – which
include market research company AC Nielsen and TV audience ratings group Nielsen Media Research – would be better value for shareholders.
KVAM would prefer a US CEO – or one with American experience – to take over. While VNU is a Netherlands-based company, most of its operations are US-based.
VNU brought in Finsbury, led by co-founder Rupert Younger, at the end of last year after shareholders including KVAM had forced the firm to abandon a £4bn takeover of US market researcher IMS Health.
In December 2005, Valcon began negotiations with VNU's management, which later secured a higher agreed offer of €28.75 a share.
VNU publishes titles including Computing, Accountancy Age and Computeractive. Its exhibitions arm runs several trade shows including GlobalShop.