Its shares fell 9p to 73p.
Peter Barker, the former chairman, said when the interim results announcement was made in May that the company had previously come very close to a merger.
The company would not say who the potential bidders were, but market speculation had centred on Wassall, the acquisitive mini-conglomerate, which bought a 1.7 per cent stake last summer. Its chief executive, Chris Miller, said he could not comment.
Mr Barker has now resigned from the board, having relinquished the chairmanship in May. It is understood that institutional investors put pressure on the company to find a new chairman after poor results over the past two years.
Fenner passed its interim dividend in May after making just pounds 105,000 before tax in the six months to 28 February.
The group made pounds 2.3m in the comparable period the previous year.
The company also announced yesterday that the new chairman is to be Colin Cooke, chairman of Lloyd Triplex.
Mr Barker was chairman from 1982 and saw off a bid from Hawker Siddeley in 1984.
Julian Bigden takes over as group managing director, having previously run the group's US operations.
Fenner has been particularly hit by the uncertainty surrounding the future of British Coal. It is a big supplier of conveyor belts used in mining and 8 per cent of group sales go to British Coal.
The company said demand from British Coal for Fenner's conveyor belts had fallen by a third in the first half, but that had been partially offset by increased demand from overseas, notably Ukraine.
The group also produces power transmission equipment and fluid power products.Reuse content