The ECB is, however, for the first time considering using a possible exemption to the rule, which it can activate if it establishes that both Qatar and HNA exert significant influence on the bank despite owning a stake of less than 10 percent, the paper said.

Qatar, which has been a Deutsche Bank shareholder since 2014, and HNA, which acquired its stake this year, have each been granted a Deutsche Bank board seat.

Due to the generally low number of shareholders showing up at annual general meetings the two investors can factually block important decisions.

“It looks like both will be treated as if they held more than 10 percent,” a source told the paper, which also reported that HNA’s investment in Deutsche Bank shares prompted the ECB’s move.

Last week, Germany became the first European Union country to tighten its rules on foreign corporate takeovers, following a series of Chinese deals giving access to Western technology and expertise.