Wigan Warriors reported an operating loss of nearly £1.4million last year.
The club's two-game tour of Australia - which finished "significantly below budget" - was blamed for a large part of that shortfall, according to accounts filed at Companies House.
The £1.4m loss is nearly £1m more than 2017 and, indeed, the same amount lost over the previous three years combined.
Although Wigan stormed to Grand Final glory in Shaun Wane's final year, turnover dropped by £600,000 to £6.5m.
But the club's expenditure crept towards £8m, leaving them with a deficit of £1.4m and a net loss of £1.2m, after tax.
Chairman Ian Lenagan, who owns 89 per cent of the club through Lenagan Investments Ltd, has once again plugged the gap from his own funds.
Wigan's average attendance dropped from 13,983 to 11,708 last season, the last under the Super-8s structure. And the report, filed this week, says they took a financial hit from their decision to stage two matches in Australia.
Wane's side faced Hull FC in front of 12,416 fans in Wollongong - a ground-breaking first Super League match staged outside of Europe. They then played Souths in a double-header friendly the following week, with 18,721 watching the match in Sydney.
Wigan made it clear in advance they hoped to make a profit from the venture, but the report says "the attendance for the Sydney game was significantly below budget (leading to) a disappointing financial outcome."
The report reveals Wigan received transfer fees of £175,000 - thought to be for John Bateman's move to Canberra - and also sold the Lotto shop for £120,000.
The number of players and coaches increased by three, to 71, while the administrative staff was down one to 29, and the amount paid in wages went up four per cent.
Directors received £109,465 remuneration, nearly double the figure of the previous year, and the cost of renting the DW Stadium was £295,000, similar to in 2017.
The independent auditor, operating under more stringent requirements, points out Wigan is reliant on Lenagan Investments Ltd. .
John Fairhurst wrote: "The existence of operating losses, working capital requirements and reliance upon Lenagan Investments Limited indicate that a material uncertainty exists that may cast significant doubt on the company's ability to continue as a going concern."
Wigan have recently moved to a training base at Robin Park and the report reveals their former site, at Orrell's Edge Hall Road, is valued at £2.2m.
They have a 25 year renewable licence to use the Latics-owned DW Stadium at rates determined by match income.
Warriors' finance director David Moore wrote in the report: "The board recognise that the heightened levels of operating losses incurred in the year do not represent a sustainable position for the club.
"The board are committed to significantly reducing the level of the operating loss for 2019 and beyond."
Wigan have signed two marquee players for next season - George Burgess and Jackson Hastings - but still intend to lower overall wages which, combined with a projected rise in attendance, would reduce the deficit.
Lenagan has never shied away from the fact he wants to break even or make a profit, which would be reinvested into the club he has owned for 12 years. He is joined on the board by executive director Kris Radlinski, Dr Chris Brookes, Winston Higham and Moore.