By Kate Burgess and Anousha Sakoui and Jack Farchy

Fidelity Worldwide Investments, the London-based fund manager, has joined a growing chorus of Xstrata shareholders seeking a change in the terms proposed by commodity trader Glencore to combine the two companies.

Fidelity is a top 10 shareholder of London-listed miner Xstrata, with 1.5 per cent, as well as a 2.3 per cent stake in Glencore. ?We are supporting the deal in principle but think the terms need to be revisited,? said Fidelity.

This brings the tally of shareholders opposed to the terms of the deal to around 8 per cent, according to a survey of investors by the Financial Times. The companies are expected to seek shareholder approval for the all-share merger, which would be the largest-ever mining deal and create a company with an equity value of around $90bn, in a few months time.

Only 16 per cent of Xstrata shareholders are needed to block the vote, but the numbers could be lower if not all shareholders vote at the meeting or by proxy.

Fidelity?s statement comes after a week of meetings between shareholders and Mick Davis, chief executive of Xstrata and the proposed leader of the combined company. Ivan Glasenberg, chief executive of Glencore and its biggest shareholder, will be deputy CEO.

Another investor said that many shareholders had ?hardened against the deal? following these meetings. Further meetings with shareholders are expected.

Earlier this week Standard Life, the miner?s fifth-biggest shareholder with a holding of about 2 per cent, said it would vote against the deal. David Cumming, head of equities at the company, said: ?Although we see some merit in the merger of Xstrata and Glencore the proposed exchange ratio clearly undervalues Xstrata?s assets and future earnings contribution.? Standard Life also owns a 0.3 per cent stake in Glencore.

A group including those two funds, Schroders, Royal London Asset Management – and two other funds that have told the FT they oppose the terms – holds a total of around 8 per cent of Xstrata?s shares.

Opponents of the deal have said that the offer of 2.8 Glencore shares for every Xstrata share undervalues the miner of thermal coal, copper, nickel and zinc. Glencore, the world?s largest commodities trader, would end up with a 55 per cent stake in the combined group

Some analysts believe that Xstrata?s shareholders would vote for the deal if the ratio was raised to 3.0. Another offer that could also be acceptable is a special dividend, said the analysts, which could be paid either before or after the merger to shareholders of Xstrata excluding Glencore, which holds a 34 per cent stake in the miner.

Jake Greenberg, a metals and mining specialist for Jefferies, the US investment bank, said he had spoken to ?a number? of ?large institutional Xstrata shareholders? who expressed similar dissatisfaction with the terms of the deal as Schroders and Standard Life.

? The Financial Times Limited 2012