Harry Potter publisher Bloomsbury lost almost a third of its value after the firm fired out a profits warning.
The company admitted it had been stung by poor Christmas sales which could end up slashing full-year profits by as much as 75 per cent.
Analysts had been hoping the publisher would bank profits of around £20 million, but Bloomsbury said the figure was more likely to be in the region of £5 million.
The stock market reacted by sending Bloomsbury shares down 29 per cent - the fall wiped £66 million off the value of the publisher.
On top of poor sales, the group has endured delays while trying to seal a number of key contracts, which has affected its ability to sell on reference rights to other companies.
However, the Bloomsbury insisted it could improve if a number of issues are resolved before the end of the group's financial year on December 31.
It said: "If these major pending rights deals are completed and retail sales increase, profits before tax will be close to market expectations."
But Roddy Davidson, an analyst at Altium Securities, said this was "a forlorn hope".
He said: "This would be a staggeringly poor result against our and consensus estimates of around £20 million, particularly for a company which has been lauded for the reliability of its financial performance.
"We note the company also states profits before tax will be close to market expectations if pending rights deals are completed and retail sales increase - although this strikes us a forlorn hope."
Record-breaking sales of the hardback edition of Harry Potter and the Half-Blood Prince ensured Bloomsbury banked profits of £20 million last year.
But, despite the release of the paperback version in June, it seems the publisher has failed to entice bookworms to pick up copies of its latest publications.
Its best-selling titles in the last few months have included My Take by former Take That star Gary Barlow, Amir Khan -A Boy from Bolton, Al Gore's Inconvenient Truth and Schott's Original Miscellany.
Although Bloomsbury, which this year also published The Two of Us by Sheila Hancock, insisted in a statement: "The board remains confident of a satisfactory outcome for 2007."
It also looked to calm nerves by pointing out cash on the company balance sheet was expected to be "not less than £20 million". l Debenhams blamed tough trading conditions for a 4.7 per cent fall in same store sales in the 14 weeks since the start of September.
Debenhams, which has a flagship store in the Bull-ring Shopping Centre in Birmingham, saw its trading figures worsen in November and December.
It described trading as "difficult".