Championship club West Brom gave a loan of £4.95m to a company owned by chairman and owner Guochuan Lai to help it through the coronavirus pandemic.
The details of the loan are contained in West Brom's accounts to June 2021, released on Thursday.
Lai says he will return the money, with £50,000 interest, by 31 December 2022 after the initial repayment date was moved from 15 September.
"I will repay the loan in full," he told the club website.
The news will come as a shock to West Brom fans as it took money out of the club that could have been used for transfers both last summer and this, as the club tries to return to the Premier League.
"The club's annual accounts for the 2020-21 season detail a loan to Wisdom Smart Corporation Limited, a related party to me. Regrettably, the Covid-19 pandemic saw my international businesses suffer, particularly those in the hospitality and entertainment sector, which experienced an almost complete closure for long periods, and in March 2021 I received a loan from the football club," said Lai.
"The upturn in the global economy has brought with it greater positivity and I can confirm I will repay the loan in full, with interest, by the end of the current calendar year and the funds will be available to the club during the January 2023 transfer window.
"I remain committed to returning the football club to the Premier League and I am confident we will be able to compete for promotion from the Championship this coming season."