De La Rue, the company that prints the UK’s banknotes, has said there is a risk that the firm will collapse if its turnaround plan fails to work.
The announcement came as it suspended its dividend and reported a loss in the first half of its financial year.
De La Rue said its warning was based on a worst-case scenario.
However, it concluded that there was “a material uncertainty that casts significant doubt on the group’s ability to operate as a going concern”.
De La Rue prints about a third of the world’s banknotes and employs more than 2,500 people globally.
It appointed a new chief executive, Clive Vacher, in October as part of a management shake-up.
Shares fell 20% on the news in early trading on Tuesday.
De La Rue has faced some big setbacks in the past two years, including the loss of the post-Brexit UK passport printing contract in March 2018.
In May last year, it had to write off £18m after Venezuela’s central bank failed to pay its bills.
It is also under investigation by the Serious Fraud Office in connection with “suspected corruption” in South Sudan.
The company reported a £12.1m pre-tax loss for the six months to 28 September, compared with a £7.1m profit in the same period last year.
In its results statement, the company said it was accelerating its restructuring plan, including a reduction in overhead costs.
It is also planning new banknote security feature products to bolster its position in the “increasingly competitive” banknote market.
“De La Rue is teetering on the brink,” said Neil Wilson, chief market analyst for Markets.com.
“Bad management and decisions seems to be the main reason for the malaise.”