Cardiff City lost nearly £12m during their debut season in the Premier League.
The club's latest accounts, for the year ending May 2014, also show the Bluebirds owe around £174m - most of it to owner Vincent Tan.
This was despite revenue increasing more than five fold to almost £80m.
The club's annual report says support from Malaysian investors "will continue" as long as "the business develops as planned".
The financial figures showed that the club's broadcasting and commercial income rose from from £8m to more than £70m.
Wages and salaries went up from just over £27m to £46m.
|BBC Wales football correspondent Rob Phillips|
|"The accounts underline the club's reliance on controversial Malaysian backer Vincent Tan.He has not yet attended a game this season and Cardiff City manager Russell Slade attempted to cut the player wage bill during the January transfer window.But it is clear the operation still relies heavily on Tan. He has pledged he will convert the club's debt into equity, but that will not happen until the club's legal battle over creditors the Langstone Corporation reaches a conclusion."|
During their time in the Premier League Cardiff sacked Malky Mackay and replaced him with Ole Gunnar Solskjaer.
The club said they paid just over £2m on "exceptional costs" relating to the change of football and senior management.
The accounts show the club received loans of around £130m - mainly from Tan, but also including a loan of £7.5m from Torman Finance, understood to be chairman Mehmet Dalman's company.
The report adds: "Following relegation from the Barclays Premier League the owners are aware that they needed to again invest in strengthening the playing squad, but that they needed to spend wisely.
"Whilst long term funding is not guaranteed, the Malaysian investors have indicated that providing the business develops as planned, they will continue to support the company in the foreseeable future and provide additional finances in order that it can settle its liabilities."
Tan has previously said he will convert the club's debt into equity.
Keith Morgan, a chartered accountant who sits on the board of Cardiff City Supporters Trust, told BBC Radio Wales Sport: "The club is highly insolvent.
"It has far more liabilities than assets and at any point in time it could be called upon to repay that debt owed to Vincent Tan."