Xstrata's fourth largest shareholder, Standard Life Investments, said it will vote against the recommended merger between the miner and Glencore because the deal "clearly undervalues" the miner.
Mining company Xstrata has formally announced its intention to merge with Glencore, the world's largest commodities trader, creating a commodities 'powerhouse'.
Glencore and Xstrata are in advanced talks about a $80bn merger that could reshape the mining industry.
LVAM's Graham Ashby and Cavendish's Paul Mumford have both ruled out buying into Glencore, although its share price has dived 13% since listing on the London market in May.
Glencore's share price has risen in early trading after the group reported a 57% increase in profits for the first half of the year.
The Financial Services Authority (FSA) has warned investors against buying shares from cold callers claiming to be from Glencore International Plc.
The big event in May for the London stock market was the IPO of Glencore. Many investors are unsettled about the logic of listing companies on the LSE that have little or no economic footprint in the UK.
Commodities giant Glencore today said it is not mulling a bid for peer ENRC.
Shortsellers rounded on Glencore on the first day of official trading of shares in the commodities giant, casting a shadow over its blockbuster £37bn listing on the London stock exchange, the Guardian reports.