Teixeira Duarte was a founding shareholder of "Banco Comercial Português, S.A." in 1985, having progressively followed successive capital increases and reinforced its strategic shareholding. In 2010 it became the Bank's largest national shareholder and the second largest in overall terms, with 6.9% of its share capital.

Teixeira Duarte's relative position in BCP's share capital subsequently decreased and in 2013 it fell below 2%, no longer being considered a qualifying holding.

Also in 1985 the multi-year work began on the construction of the railway bridge over the Douro River and respective accesses, through FERDOURO ACE, which Teixeira Duarte integrated with other companies, and also the construction of school buildings and the rehabilitation of buildings for the installation of bank branches, in a phase of commercial growth of banks in Portugal.

The construction of the Águeda-Albergaria subsection of the Northern Motorway was begun, followed, in 1986, by the Coimbra Sul junction. Later, in 1988, construction of the Aveiras de Cima/Santarém/Torres Novas sections.