The boss of delivery service UK Mail has stepped down with immediate effect just a week after the group warned over profits for the second time in three months.
Guy Buswell left by "mutual agreement", according to UK Mail, and the group has launched a search for his replacement.
Company founder and non-executive chairman Peter Kane will become executive chairman on an interim basis.
Mr Buswell's departure comes after the firm has lost more than 40% of its stock market value since February following trading woes and problems with its new automated warehouse.
Shares were down another 4% after news of Mr Buswell's departure, which comes after a 10 year tenure in charge.
There was no statement from him in the announcement of his departure, but Mr Kane said: "The board and I would like to thank Guy for his contribution to the company over the past 10 years in his role as chief executive and wish him well for the future."
UK Mail last week revealed half-year pre-tax profits crashed by 81% to £2.2 million and warned over a further hit next year.
The interim profits blow came after its main hub found it difficult coping with odd-shaped parcels its machines could not sort.
The group said alongside its half-year results that these problems were taking longer to resolve than anticipated, and although it planned to meet its reduced full-year targets this year, its "expectations for the next financial year have softened slightly".
It added it was expected to take another 12 months to fully resolve the problems at its new hub.
The alert came after it warned in August that annual profits will be as much as £10 million, or 50%, lower than expected after it lost out on business due to its relocation to Ryton near Coventry.
UK Mail recently moved from Birmingham to Ryton near Coventry to make way from the proposed High Speed 2 rail route.
The business, which originally began as a Harrow taxi firm in 1971, has previously said its move to Ryton was "the single most significant strategic development in the group's history".