ValueAct is reported to be seeking support from other shareholders for its $23 per share bid, which values Acxiom at $2bn (£1.1bn). ValueAct's managing partner Jeffrey Ubben has previously campaigned for the management to do more to raise the company's share price.
ValueAct has not yet formally tabled a bid to the Acxiom board. It proposed an offer to Acxiom's board in June which was rejected in last month.
At the time, the board described ValueAct's proposal to negotiate "wholly opportunistic and an attempt to capitalise on recent revenue shortfalls compared to company expectations".
Charles Morgan, Acxiom company leader and chairman, suggested that Ubben's recent criticism of the management was linked to his failure to secure a board position.
"We are disappointed that Mr Ubben's and ValueAct's positive views of our company and its leadership abruptly changed following the Acxiom nominating committee's decision in late May to deny Mr Ubben's request for a seat on the Acxiom board," Morgan said.
The offer was rejected as Acxiom reported its first quarter profits fell by 48% while turnover grew 7% from $289m to $310.3m.
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