Delta Air Lines (DL, Atlanta Hartsfield Jackson) has increased its stake in Hanjin KAL, the parent company of Korean Air (KE, Seoul Incheon), from 9.21% to 11%, it announced in a report to the South Korean securities exchange on February 21.

The move now exceeds Delta CEO Ed Bastian’s pledge in June 2019 that his airline planned to raise its stake to 10% over time.

The US carrier, which has a partnership with Korean Air on routes and networks, last increased its stake in Hanjin KAL in September 2019, to 9.21%. It bought an initial stake of 4.3% in the Korean flag carrier’s parent in June 2019 and upgraded this to 5.13% two months later.

The latest purchase comes amid a family feud between Korean Air CEO and group chairman Cho Won-tae and his older sister Cho Hyun-ah, who, as previously reported, has been building support to appoint a professional chief executive to run the conglomerate and boost its flagging share prices.

She has joined forces with activist hedge fund Korea Corporate Governance Improvement (KCGI), Hanjin’s second-biggest shareholder, and Bando Construction in an alliance that holds a combined 37.08% stake in Hanjin KAL, ahead of a Hanjin KAL shareholders meeting in March. Her brother’s term as chairman expires in March.

KCGI objected to Delta Air Lines’ move, saying in a statement on February 25: “The true intention behind Delta Air’s increase in Hanjin KAL’s voting rights is questionable.”

Its disapproval comes amid reports that Delta might act as a “white knight” to vote in favour of the Hanjin Group’s controlling family, given its partnership with Korean Air since 2018 in a transpacific joint venture, the Korea Herald reported. The US airline should have invested in Korean Air, not its holding company, KCGI argued. The fund speculated that Delta might be using its creeping stake to strengthen its hand in negotiating the distribution of revenue from the joint venture.