The company is lowering its profit forecast for the year to between £5m and £7m after trading in September was "extremely poor."
Read more: Bonmarche names new chief executive
Bonmarche's fortunes were hit by "unseasonably hot weather", the retailer said, which hampered sales of its autumnal stock. The company managed to sell much of its left over summer stock - and will have less residual stock than last year - but had too much autumn wear to shift.
Unsurprising profit warning from @bonmarche - market reaction (massive share price hit) quite amusing; didn't they see it coming??— Jonathan De Mello (@DeMelloRetail) September 21, 2016
As a result, like-for-like sales for the second quarter are expected to fall by approximately eight per cent and the like-for-like sales for the first half of the year are also expected to drop by eight per cent.
Markets responded well when former Asda director Helen Connolly became Bonmarche's chief executive in March - but traders seem to feel differently about the retailer's future today. Connolly admitted this morning that the company's effectiveness "needs to improve".
I was attracted to Bonmarche by its potential to grow as a business serving the 50 plus women's value clothing market. My early impressions have underpinned this, and I am currently formulating my plans for the future.
The direction of travel is right, but the effectiveness of execution needs to improve.
My plans are therefore likely to focus on improving the clarity of the customer proposition and operational improvements in all channels rather than a major strategic repositioning.