FRANKFURT/BEIJING - HNA Group Co, the Chinese aviation-to-hotels conglomerate, increased its stake in Deutsche Bank AG to almost 10 percent, overtaking Blackrock Inc as the top shareholder in Europe's biggest investment bank.

HNA's holding in Germany's biggest bank rose to 9.92 percent, according to a regulatory filing on Tuesday by investment entities acting on HNA's behalf.

The conglomerate initially reported a 3 percent stake in Deutsche Bank in February, saying at the time that it may increase its holding, while intending to remain below 10 percent. It disclosed a stake of almost 4.8 percent in March.