The troubled telecoms group has instructed Morgan Stanley to manage the sale of the fund and it is understood that the process is already under way.
Though Ericsson wanted to buy Marconi, it is understood to have been adamant that it would not take responsibility for the problem with its pension scheme.
Marconi, which has sold most of its business to Ericsson, is unusual in having a large pension liability compared with its market capitalisation. Its pension fund covers 38,000 pensioners and more than 30,000 deferred members — workers who have moved on to other employers and have yet to call on their pension benefits. Against this, there are fewer than 3,000 workers contributing to the scheme. Under FRS17 the Marconi pension scheme deficit stands at £109 million. Under the terms of the deal the remaining part of Marconi — to be renamed Telent — has agreed with the regulator to spend £185 million shoring up its deficit. It has also agreed to set aside nearly £500 million for future payments.