Herbert Diess, CEO of German carmaker Volkswagen addresses the media during the annual news conference at the Volkswagen plant in Wolfsburg, Germany March 12, 2019. REUTERS/Fabian Bimmer

WOLFSBURG, Germany (Reuters) - Volkswagen VOWG_p.DE Chief Executive Herbert Diess on Tuesday said the multi-brand conglomerate was reviewing its portfolio of brands as it seeks to slim down and hike profitability.

“We are reviewing our brand portfolio, in the second half of the year we can talk more about this,” Diess told analysts at a news conference in Wolfsburg, Germany.

The 12-brand passenger car and trucks maker still has valuable non-core assets but Porsche and Skoda are not up for sale, Diess said.

“Sometimes it is underestimated how much Porsche is intertwined in the group. They depend on 80 percent Audi platforms. The Porsche model 17.5 percent margin is only possible within the group. The same applies to Skoda,” Diess said.

Without access to group-wide vehicle technologies, Skoda and Porsche would be too small to develop next generation vehicle platforms, Diess said.