The Scottish Government loaned BiFab £19 million during 2017-18 and then converted this into shares.
Audit Scotland, however, reassessed the value of the loan later in 2018 and judged that the valuation of the loan was impaired by £13 million, resulting in a net valuation of just £6 million.
Details of the loan to BiFab only go up to March 2018.
A Scottish Government spokesperson said: “The Scottish Government provided a loan facility to BiFab to allow completion of the works on the Beatrice contracts. It was agreed that these funds would be converted to a minority equity stake in BiFab, not exceeding 38 per cent.”
Any further loans made to BiFab will be stated in the Scottish Government’s 2018-19 accounts, published later this year.
The Scottish Government took a minority shareholding in the company as part of an agreement when DF Barnes acquired BiFab last year.
BiFab has been fighting to secure work since then.
It is understood engineering company has secured a contract for the Neart Na Gaoithe (NnG) wind farm in the Firth of Forth.
The deal is believed to be for eight of 53 jacket foundations and could create more than 200 jobs.
However, workers unions Unite and GMB called the contract a “paltry return” and “a very small crumb of comfort to the communities in Methil and Burntisland”.