Donald Trump's Turnberry golf resort lost nearly £3.4m last year.
The historic venue has remained in the red since it was bought by the US President for almost £40m in 2014.
Newly-published accounts show its losses so far add up to around £30m.
Eric Trump, who runs the company behind Turnberry on his father's behalf, suggested poor Scottish weather may have been partly responsible.
"The group operates in an industry which is both competitive and challenging, factors which can be heightened by adverse weather conditions," he advised in his annual director's report.
The Trump Organisation claims to have invested £200m in Turnberry since taking ownership.
However, accounts published between 2014 and 2017 show just £54.9m has been spent on so-called "tangible assets".
Turnberry also reported losses for several years before it was bought by the Trump Organisation, which opened a new course at the resort last year.
It has also raised annual membership fees by more than a third, to over £2500.
The President's course in Aberdeenshire, Trump International, has likewise reported a loss each year since it opened.