New Delhi, Oct. 12 -- Tata Motors Ltd has raised its offer price for Iveco Group NV, but three major institutional shareholders have yet to tender their shares, putting the acquisition at risk as the 26 October deadline approaches. The tender offer had attracted acceptances for just 28.4% of the shares by the latest available count, with less than two weeks remaining.

The company raised its offer price by 2% to €14.40 per share on 9 October, after activist investor Petrus Advisers publicly rejected the original offer on 29 September, arguing that it undervalued the Italian commercial vehicle maker. The revised offer is Tata Motors' "best and final" price, the company said.

The three investors-hedge funds Davidson Kempner and Syqua...