Leighton fell under Spanish control early last year when Hochtief increased its share from 58.77% to almost 75% and set about changing the business model to four key divisions: construction, mining, public-private partnerships, and engineering.
Hochtief stated that Leighton businesses such as Thiess, John Holland and Leighton Contractors could be "more efficiently structured" and has been steadily selling off business units ever since.
Recently John Holland was sold to the Chinese for $1.5 billion while its services division, which includes part of Thiess, is now subject to a new $1.8 billion joint venture with an American fund.
If the mooted $2 billion sale of the 1934-founded Thiess occurs it will be the biggest single transaction so far.
Leighton is targeting around $3 billion in asset sales, however a sale of its Leighton Properties to Stockland fell through just before Christmas.
Leighton is also looking to rid itself of a controlling stake in listed property developer Devine, with AVJennings expected to secure that asset.
Thiess became a part of Leighton Group in 1983 when Hochtief first bought shares in the business.
It is engaged in delivering major projects on the global stage, including for Gorgon and Wheatstone LNG projects in WA, the Epping to Chatswood rail line and Wynard Walk in New South Wales, and South Australia’s $2 billion Adelaide light rail network.
As a mining contractor Thiess has worked at coal projects such as the Lake Vermont mine in Queensland and Bayan Resources’ GroupMelak mine in Indonesia, BHP Billiton’s Mount Keith nickel mine in Western Australia and the greenfields Roper Bar iron ore mine for Western Desert Resources in the Northern Territory.