Nov 29 (Reuters) - Qatar is buying a significant minority stake in Audi's Formula One team, the Gulf country's estimated $510 billion sovereign wealth fund and the German carmaker said on Friday.

The holding will be almost a third of the team, a source familiar with the matter told Reuters after the Qatar Investment Authority (QIA) deal with Audi was announced during the first day of the Qatar Grand Prix, the penultimate of the season.

Financial terms of the deal, which builds on the Qatari state's global sports portfolio, were not disclosed. The QIA also owns a 17% stake in Germany's Volkswagen, which owns Audi.

Audi, Volkswagen's luxury brand, is set to make its Formula One debut in the 2026 season and turn Switzerland-based Sauber into its factory team, after flagging in March it would acquire 100% of the firm.

Sauber is the only team yet to score a point in 22 Formula One races this season.

Qatar's other sporting holdings include France's Ligue 1 club Paris St Germain, which is owned by Qatar Sports Investments (QSI), a state-backed body founded by the emir of Qatar, Sheikh Tamim bin Hamad Al Thani.

QSI also acquired World Padel Tour from its organisers Damm last year and unified the world's professional tour under one entity, ending a power struggle in the sport.

The Gulf state's Sheikh Jassim bin Hamad Al Thani, son of a former prime minister, last year bid $6 billion for English Premier League club Manchester United ( MANU ) before dropping out.