Williams has revealed it recorded a more than $50 million loss in 2014.
The Grove team, listed on the Frankfurt stock exchange, enjoyed a surge in performance last year following a long slump, but took a financial hit due to "lower revenue and higher costs".
In a statement, Williams explained that it had embarked on a "turnaround strategy" in 2013 "following a number of years of deteriorating performance".
"Consequently, and as anticipated, 2014 was a year of transition," the team admitted, due in part to lower income and sponsorship as a result of finishing a woeful ninth in the 2013 world championship.
Higher costs, Williams added, were due to "the introduction of the new hybrid power unit into formula one".
But the team said that due to its strong results on the track last year, "that success will be reflected in increased commercial rights and sponsorship income this year".
"Therefore, the financial results for 2015 will be materially more favourable than 2014," it added.
Chief executive Mike O'Driscoll said: "In 2014 we made very good progress, investing significantly in people, facilities and technology which we believe will provide a solid foundation for the future."