Daimler has cautioned that it must fulfill its existing partnership obligations with Geely local rival BAIC.
Executives from Daimler and Volvo have hinted at internal resistance to sharing intellectual property with Geely.
Riding on a few years of success after buying Volvo Cars, the Chinese automaker's founder, Li Shufu, recently bought a nearly 10-percent stake in Daimler and a sizable minority stake in Volvo Trucks.
Some analysts voiced suspicions that Li hopes to strengthen Geely's competitive edge with help from Mercedes-Benz technology. Automotive historians, meanwhile, pointed out that the Chinese billionaire's first pet project in the automotive arena involved reverse-engineering an E-Class to build a glaring "Chinese Mercedes" knockoff.
"Handing Volvo and Geely our Mercedes technology is not win-win," an unnamed Mercedes-Benz executive recently told Reuters.
Daimler chief Dieter Zetsche maintained a more neutral tone in an official statement, welcoming the new shareholder but cautioning that Mercedes-Benz must fulfill its existing partnership obligations with Geely rival BAIC.
Volvo Cars chief executive Hakan Samuelsson acknowledged another potential issue, pointing out that Daimler and Volvo are even closer competitors in the commercial truck business than Mercedes-Benz and Volvo in the passenger-car market.
"It is difficult to invest in two competitors," he said.