DEC acquired the stake when it formed an alliance with Olivetti in 1992, paying around dollars 287m. It sold yesterday for dollars 150m.
Olivetti said the sale formed part of Digital's restructuring plan announced earlier this year. In July, DEC announced a fourth- quarter loss of dollars 1.75bn, including charge of dollars 1.2bn to cover job losses. The company is cutting 20,000 jobs - about 20 per cent of the workforce. The loss for last year was dollars 2.16bn, the group's fourth in succession.
Digital said it remained committed to its partnership with Olivetti. The US group continues to sell Olivetti products under the DEC label. It also carries out some joint research with the Italian firm. Olivetti sells DEC workstations under its own brand name.
A spokesman for DEC said: 'We still have an important alliance. The relationship is changing continuously but that is to do with product life cycles.'
An Olivetti spokesman said that the co-operation accord would be reviewed. He also said the shares sold by DEC had been absorbed by the market, with institutional investors taking a large portion.