BERLIN (Reuters) - Volkswagen brands are preparing for stock market listings as a training exercise, CEO Oliver Blume told the Handelsblatt newspaper on Tuesday, as its largest shareholder began its acquisition of Porsche AG shares.

Volkswagen's listing of Porsche last Thursday, floating 12.5% of the sportscar brand on the stock market, prompted speculation of further listings as a means of unlocking value in the group that executives view as strongly undervalued.

It was also viewed as a means of giving the Porsche and Piech families, set to receive a blocking minority of 25% plus one of the voting ordinary shares, a tighter leash over the carmaker and sportscar brand.

Porsche SE officially transferred the first tranche of its shares on Tuesday, consisting of 17.5% of ordinary shares - carrying voting rights - for 7.1 billion euros ($7.04 billion), the company said.

The second tranche will be transferred at the start of next year, when Volkswagen AG shareholders are paid out 49% of the proceeds of the listing as a special dividend.

Porsche SE will be treated as if it owns the stake even before the transfer is complete, according to the prospectus for the IPO.

Meanwhile, Volkswagen is running training sessions for unlisted brands - including Audi, Lamborghini, Bentley, Skoda, Seat and Cupra - to sharpen their focus on capital markets, Blume said in the Handelsblatt interview. The results of the exercise would be presented at a capital markets day next year.

"Within the Volkswagen Group I sense a clear motivation to give capital markets a higher relevance," Blume said.

"Done wisely, it could add significant value and improve competitiveness of the group and brands," Arndt Ellinghorst, automotive expert at data firm QuantCo, said of listing further Volkswagen brands.

Porsche is already worth almost as much as its former parent, which Blume told Handelsblatt underlined the potential hidden value in the group.

Still, the Porsche listing has yet to benefit Volkswagen's valuation, with shares in the group down around 10% in part because investors switched from the former parent to the sportscar brand.

Volkswagen Chief Financial Officer Arno Antlitz said last week that assessing a listing of battery unit PowerCo was the next priority, brushing aside possible further brand listings.

The Porsche listing relied on factors like the support of the Porsche and Piech families controlling most of Volkswagen's voting rights, which could not be guaranteed for other brands, said Tom Narayan of RBC, pointing to a listing of the battery or software divisions as the most likely next step.