Though Tianjin Tianhai, which guaranteed the loan, on Thursday announced that three accounts were temporarily frozen because of Ningbo Commerce, it didn’t specify the reason beyond saying that it was a disagreement over the repayment of debt. The episode illustrates how financial pressures have been piling up at HNA, one of the world’s most indebted companies, after the conglomerate spent tens of billions of dollars in an acquisition spree in recent years.

The situation bubbled up after a drop in Tianjin Tianhai’s stock price -- it fell 34 per cent from mid-April to early June and 25 per cent from mid-November to late December -- which triggered a margin call, the people said. Although part of the loan was paid back, Ningbo Commerce began an investigation into the HNA unit and found that those shares were being pledged to another creditor. That, combined with stricter limits on borrowings backed by pledged shares, prompted the lender to call back the entire loan, which the HNA unit failed to do, one of the people said. About 280 million yuan remained outstanding and a court dispute ensued, resulting in the frozen accounts, the people said.

In its Thursday statement, Tianjin Tianhai said that after negotiations with Ningbo Commerce, a Shanghai court ordered the accounts to be unfrozen on January 15. Tianjin Tianhai also said that the parent company became aware of the situation on January 12 -- coinciding with the day that the stock was halted from trading, pending a “major” announcement. Tianjin Tianhai said its operations haven’t been affected.

A representative for HNA couldn’t immediately comment beyond Thursday’s statement.

Tianjin Tianhai is one of six HNA units -- the others being HNA-Caissa Travel Group, Hainan HNA Infrastructure Investment Group, Bohai Capital Holding, HNA Investment Group and flagship Hainan Airlines Holding -- that have suspended their shares from trading this month, pending major disclosures. Another unit, CCOOP Group, has been halted from trading since November, pending the disclosure of some asset purchases.

HNA’s debts surged last year as financing costs more than doubled, according to the group’s latest half-year financial report. Since then, investor concerns about the conglomerate’s finances have increased, driving its borrowing costs higher. Some banks froze several unused credit lines to HNA units after they missed payments, people familiar with the matter said in January.

The Ningbo Commerce dispute also puts a spotlight on HNA’s extensive use of share pledges to borrow funds. According to filings and data compiled by Bloomberg, HNA and its units pledged at least US$24 billion of shares across 15 publicly traded firms as of July, including shares of Hilton Worldwide Holdings Inc. and Deutsche Bank AG.

In China, a court-ordered freeze on bank accounts and double pledging of collateral could trigger a rush among other creditors to review their exposure to the borrower and result in more banks to call in their loans. In 2014, Decheng Mining was found to have pledged the same metals stockpiles three times over to obtain more than 2.7 billion yuan of loans in China’s Qingdao port, which triggered an industry-wide curb in commodities financing.