Bournemouth's latest accounts show the club made a loss after tax of £32.4million – up from £10.9m for the same period last year.
The Cherries have found themselves battling for Premier League survival this season.
Eddie Howe's side sit in 18th place, but level on points with the two sides above them before the season was halted by the global coronavirus pandemic.
On Wednesday afternoon, the club published the accounts of holding company AFC Bournemouth Limited for the year ending 30th June 2019.
As well as the increase in loss, club turnover was down by £3.7m, from £134.9m in 2018, to £131.1m in 2018.
Bournemouth said the decrease was "mainly attributed to a lower Premier League finish of 14th place".
Non-Premier League revenue remained "broadly similar" at £15.5m, which Bournemouth said "reinforces the club's continuing off-field progression".
Bournemouth's spending over the period was £94.2m, compared with £55.8m in the previous period, with the likes of Jefferson Lerma, David Brooks and Dominic Solanke all having come into the Vitality Stadium, which the club said "demonstrates the board's commitment to the continued development of the playing squad".
Wages were also up from £101.9m in 2018 to £110.9m in 2019 as Bournemouth looked to "attract and maintain the calibre of playing and team management staff necessary to allow the club to compete in the league, with the aim of maintaining Premier League status".
The figures, though, did not include the income from sales last summer, including Tyrone Mings' £20million switch to Aston Villa and Lys Mousset joining newly-promoted Sheffield United, which would have helped offset some of the losses.
Commenting on the results, Bournemouth chief executive Neill Blake said: "The 2018/19 season saw the club competing in the Premier League, finishing in 14th place with 45 points. That was enough to secure Premier League status for a fifth consecutive season.
"During the financial year, the club's focus was to consolidate its position in the Premier League through targeted expenditure on assets and expertise in the playing squad and supporting infrastructure.
"The directors continue to maintain close control over cash flow and continue to develop and maintain policies with the aim of ensuring the club is run in a sustainable and successful manner.
"These policies are seen as vital in order to keep control over all expenditure that the club commits to.
"The club sees retention of key staff as a key ingredient to success and the directors considers the financial position of the company to be satisfactory.
"Shortly after the year end, the club sold three players for a profit of £22.6m.
"Clearly, if these sales had been made before 30th June 2019, this would have removed a large portion of the loss for the year."