(Reuters) - Boeing Co (N:BA) had pumped in more than 100 million pounds ($130 million) into Britain's Monarch Airlines [MONA.UL] which collapsed last week, the Financial Times reported on Monday.
The capital infusion, through Monarch's offshore holding company Petrol Jersey, was carried out in several tranches between October 2016 and March this year, the FT said.
"We do not publicly comment on our customers' financial arrangements but ensure we are always compliant with trade law" Boeing said in a statement to Reuters.
The airline's private equity owner, Greybull Capital, declined to comment on details of the financing, saying that they were "commercially confidential," FT added. It denied that there had been anything secretive about the transaction.
"As a regulated body, all financing arrangements provided to Monarch were reviewed and approved by relevant authorities," Greybull told the newspaper.
Reuters could not immediately reach Greybull for comment outside regular business hours.
Last year, Monarch secured a 165 million pound lifeline from Greybull, enabling the airline to renew a key operating license and fund new aircraft.
The equity investment had been agreed only hours before its operating license was due to expire, allowing the airline, which sells flights and package holidays to tourist destinations, to keep flying.
The 48-year-old airline had said that the investment would fund the replacement of its Airbus jets with more fuel-efficient Boeing 737 MAX-8 aircraft between 2018 and 2021.
The low-cost carrier is the largest British airline to go bust, affecting nearly 900,000 passengers.