Baugur has increased its stake in Debenhams to 11%.
Shares in Baugur closed down 1p at 120p. The shares have fallen sharply since they floated at 195p a share last year, following a profit warning earlier this year.
Debenhams has announced plans to speed up its store refurbishment programme. However, City analysts have argued that the department store has been deprived of investment under private equity ownership, and are unconvinced that it can win back customers.