Outgoing chairman Jim Mann says Kilmarnock Football Club "must do better" after reporting a loss of £724,406 for the year to 30 May 2015.
Mann, who will step down at the club's annual meeting later this month, also stated the board's desire for new investors in the club.
"Losses on this scale are unsustainable in the longer term," he said.
"And urgent action is being taken to stem them and to increase income via season ticket and match-day pricing."
It is the first set of accounts since the Scottish Premiership club reorganised their finances in a deal that eliminated its debt in March 2014.
One of the main reasons for such a heavy loss - up from £453,272 for the previous year - was their 10th-place finish in the Premiership last season having budgeted for seventh.
Mann described this as "a very disappointing outcome" that had the effect of reduced income, poor attendances and lower than expected season ticket sales.
The warning signs are also there for the present financial year, with the threat of relegation hanging over the Ayrshire club.
Kilmarnock currently sit in the relegation play-off spot, eight points above bottom side Dundee United and four points behind 10th-placed Hamilton Academical with five games remaining.
"In a recent BBC Scotland survey, we were shown to be the least expensive Premiership club to support in a number of categories," said Mann.
"Despite this, attendances and season ticket sales have continued to fall and this is a major concern for the club."
At last year's AGM, following the restructuring of the finances that left Killie debt free without bank overdraft facilities, Mann said they needed to be a financially self-sufficient club.
The hope was that this would come from a combination of well-controlled costs, success on the field, player sales and performances that would drive higher attendances and season ticket sales.
"Our report card on this would read, must do better, and this is clearly the major focus for the board," Mann added.
The club and the Killie Trust supporters group are currently working together on a scheme that will raise working capital through fan investment.
As part of this initiative, which they hope to launch in the next few months, supporters will be given representation on the board.