When a Chinese billionaire became Daimler AG's biggest shareholder in 2018, it caused quite a stir. Another Chinese investor took an even bigger stake the following year, the Mercedes-Benz maker just disclosed for the first time.

Daimler announced Monday that BAIC Automotive Group Co. almost doubled its stake in the manufacturer to 9.98% in 2019. Taken together with the 9.7% holding that Li Shufu, the owner of Zhejiang Geely Holding Group, has had since 2018, it means two Chinese shareholders have controlled almost 20% of Daimler, roughly a third more than previously known.

The German automaker didn't need to disclose the change in shareholding because BAIC stopped short of 10%, a Daimler spokesman said. The companies decided to make the announcement in the wake of Daimler's spinoff of its truck division, which will bring about greater transparency, the spokesman said. BAIC has agreed not to increase its holding any further.

"BAIC's shareholding is a reflection of their commitment to our joint successful manufacturing and development alliance in the world's biggest car market," Daimler Chief Executive Officer Ola Kallenius said in a statement.

It's unclear whether the lag time between BAIC acquiring a bigger holding and Daimler's announcement will rekindle scrutiny of disclosure rules and China's growing influence over iconic German companies. Financial-markets regulator BaFin probed whether Geely disclosed Li's stake in a timely enough manner in 2018, and Germany's interim economy minister at the time raised concerns that Geely would learn about Daimler's strategic plans.

Deutsche Bank AG's Qatari shareholders, two investment vehicles known as Paramount Services Holdings Ltd and Supreme Universal Holdings Ltd., each hold 3.05%, according to the lender's website. But the bank in 2016 said that each of them have increased their stake to "just under" 5%, leaving open the possibility that they're just short of the next disclosure threshold.

Porsche in the early 2000s quietly built up a stake of around 74% in Volkswagen AG, partly through options, as it was seeking an eventual acquisition. The move faltered, resulting in Volkswagen fully integrating the iconic sports-car brand in 2012 to end a seven-year takeover saga.

Daimler referred to its partnership with BAIC as "a role model for Sino-German cooperation for almost two decades." The German carmaker owns 49% of a joint venture with state-owned BAIC Motor Corp. and has expressed interest in raising its stake to gain control of the unit after Chinese authorities eased local ownership rules. The companies have been collaborating on vehicle development and production since 2003.

Daimler also owns 9.55% of BAIC's Hong Kong-listed unit BAIC Motor and 2.46% in Shanghai-listed BAIC BluePark.

BAIC's bigger stake in Daimler underlines the growing presence of Chinese companies in the European auto industry. Geely owns British sports-car and racing business Lotus and has turned around Volvo Car AB after the Swedish manufacturer languished as part of Ford Motor Co.

Dongfeng Motor Group Co. holds about 4.5% in Jeep maker Stellantis NV. BAIC also owns a 6.5% stake in Daimler Truck Holding AG, according to a spokesman for the German truckmaker.

Meanwhile, Chinese electric-vehicle startups, including Nio Inc. and BYD Co., are pushing to expand in Europe to generate more revenue outside their home market and benefit from growing EV sales in the region. Western carmakers including Daimler, BMW AG and Volkswagen have shifted some of their manufacturing to China to gain a stronger foothold in the market.

Daimler's board earlier this month backed investments totaling 60 billion euros ($68 billion) for luxury cars and vans from next year to 2026. After years of criticism for being late to adopt purely battery-powered cars, the manufacturer stepped up its game this year with the launch of the EQS, the electric version of its flagship S-Class.

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