In a disclosure document issued by the London Stock Exchange, Active Value was revealed to have bought another 2.5m shares at 2.95p, bringing its holding to 102,388,099 shares, or 24.53% of Cordiant.
It follows the disclosure on Friday that Active Value had raised its stake from 16.7% to 23.94%.
WPP needs the support of 75% of shareholders for its bid to be successful. If Active Value, which opposed the WPP deal, can muster more than that it will be able to stop Sir Martin Sorrell's bid for Cordiant.
At the weekend it was reported that Active Value had approached Grey Global Group to help in its battle against WPP, confirming it is searching for allies to stop the deal, which gives shareholders only 拢10m.
Julian Treger and Bryan Myerson, who run Active Value, are now virtually in sight of the holding they need to stop WPP's bid at a shareholder meeting next month.
Myerson and Treger could seek a wider alliance, taking in Cerberus, the US hedge fund that speaks for 拢80m of Cordiant's debts.
If they do stop the 拢266m deal, it will likely force Cordiant into administration where its prized assets will be picked off. The other alternative is a rival bid, but that would have to weigh in at around 拢300m to be successful.
Active Value had previously opposed early efforts by hedge fund Cerberus to force Cordiant into administration, allowing it and the French advertising company Publicis Groupe to pick off the assets, but with WPP's deal moving quickly ahead Active Value is running out of options.
Grey, like WPP, is interested in acquiring the HealthWorld business and the remaining bits of Bates, which it can use to strengthen its own agency network, Grey Advertising.
Despite moves by Active Value, analysts still believe that WPP's bid, which is favoured by Cordiant's banks and its board, has a good chance of winning out.
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