The review by Morgan Stanley and Goldman Sachs is expected to result in the sale of its automotive components division and possibly its paper technology operations.
BTR Siebe also said it is to pay pounds 34m for 48 per cent of the Japanese switches company Nippon Electric Industry, which will be merged with BRT Siebe's Japanese subsidiary.
Sources close to BTR Siebe - intending to seek approval this month to change its name to Invensys - said it would be "intelligent" to assume that divisions outside its core activities, such as automotive components, would be sold. But the formal statement said: "Speculation regarding the businesses involved, potential values and the timing of any further announcement is premature."
The review, expected to take several months, will go on alongside a restructuring that will result in 5,000 job losses in the 125,000 workforce, leading to savings of pounds 250m in three years. The value of the combined group has risen from pounds 7.6bn at the time the deal was announced to pounds 10.4bn. Outlook, page 19